diff --git a/src/lib/server/llm.ts b/src/lib/server/llm.ts
index 691da42..c8778dc 100644
--- a/src/lib/server/llm.ts
+++ b/src/lib/server/llm.ts
@@ -18,11 +18,6 @@ interface ChatMessage {
 	content: string;
 }
 
-interface Document {
-	title?: string;
-	content: string;
-}
-
 interface Student_opinion {
 	student_id: string;
 	student_conclusions: string;
@@ -55,20 +50,24 @@ export async function chatWithLLMByDocs(
 	messages: ChatMessage[],
 	mainQuestion: string,
 	secondaryGoal: string[],
-	documents: Document[],
+	documents: {
+		name: string;
+		text: string;
+	}[],
 	temperature = 0.7
 ) {
 	try {
 		if (await isHarmfulContent(messages[messages.length - 1].content)) {
 			return {
 				success: false,
+				message: '',
 				error: 'Harmful content detected'
 			};
 		}
 		const formattedDocs = documents
 			.map((doc, index) => {
-				const title = doc.title || `Document ${index + 1}`;
-				return `[${title}]:\n${doc.content}`;
+				const title = doc.name || `Document ${index + 1}`;
+				return `[${title}]:\n${doc.text}`;
 			})
 			.join('\n\n');
 
@@ -91,7 +90,7 @@ export async function chatWithLLMByDocs(
 			temperature
 		});
 
-		const result = response.choices[0].message;
+		const result = response.choices[0].message.content;
 		if (!result) {
 			throw new Error('Failed to parse response');
 		}
@@ -105,11 +104,13 @@ export async function chatWithLLMByDocs(
 		if (error instanceof z.ZodError) {
 			return {
 				success: false,
+				message: '',
 				error: 'Type error: ' + error.errors.map((e) => e.message).join(', ')
 			};
 		}
 		return {
 			success: false,
+			message: '',
 			error: 'Failed to process documents and generate response'
 		};
 	}
diff --git a/src/lib/server/parse.ts b/src/lib/server/parse.ts
new file mode 100644
index 0000000..8602e9e
--- /dev/null
+++ b/src/lib/server/parse.ts
@@ -0,0 +1,5 @@
+export async function parsePdf2Text(filePath: string): Promise<string> {
+	// TODO: pares pdf file to text
+
+	return filePath;
+}
diff --git a/src/lib/types/IndividualDiscussion.ts b/src/lib/types/IndividualDiscussion.ts
index 7ef7c50..585cbd6 100644
--- a/src/lib/types/IndividualDiscussion.ts
+++ b/src/lib/types/IndividualDiscussion.ts
@@ -5,10 +5,16 @@ export interface FirestoreIndividualDiscussion {
 	userId: string;
 	sessionId: string;
 	groupId: string;
+	goal: string;
+	subQuestions: string[];
+	resourcesTexts: {
+		name: string;
+		text: string;
+	}[];
 	history: {
 		role: 'system' | 'assistant' | 'user';
+		fileId: string | null;
 		content: string;
-		speechId: string | null;
 		timestamp: Timestamp;
 	}[];
 	summary: string;
@@ -19,10 +25,16 @@ export interface IndividualDiscussion {
 	userId: string;
 	sessionId: string;
 	groupId: string;
+	goal: string;
+	subQuestions: string[];
+	resourcesTexts: {
+		name: string;
+		text: string;
+	}[];
 	history: {
 		role: 'system' | 'assistant' | 'user';
+		fileId: string | null;
 		content: string;
-		speechId: string | null;
 		timestamp: string;
 	}[];
 	summary: string;
@@ -36,10 +48,13 @@ export function convertFirestoreIndividualDiscussion(
 		userId: data.userId,
 		sessionId: data.sessionId,
 		groupId: data.groupId,
+		goal: data.goal,
+		subQuestions: data.subQuestions,
+		resourcesTexts: data.resourcesTexts,
 		history: data.history.map((history) => ({
 			role: history.role,
+			fileId: history.fileId,
 			content: history.content,
-			speechId: history.speechId,
 			timestamp: history.timestamp.toDate().toISOString()
 		})),
 		summary: data.summary
diff --git a/src/lib/types/groupDiscussion.ts b/src/lib/types/groupDiscussion.ts
index c041026..74b4cf7 100644
--- a/src/lib/types/groupDiscussion.ts
+++ b/src/lib/types/groupDiscussion.ts
@@ -4,6 +4,7 @@ import type { Timestamp } from 'firebase-admin/firestore';
 export interface FirestoreGroupDiscussion {
 	sessionId: string;
 	groupId: string;
+	groupName: string;
 	history: {
 		name: string;
 		content: string;
@@ -20,6 +21,7 @@ export interface FirestoreGroupDiscussion {
 export interface GroupDiscussion {
 	sessionId: string;
 	groupId: string;
+	groupName: string;
 	history: {
 		name: string;
 		content: string;
@@ -37,6 +39,7 @@ export function convertFirestoreGroupDiscussion(data: FirestoreGroupDiscussion):
 	return {
 		sessionId: data.sessionId,
 		groupId: data.groupId,
+		groupName: data.groupName,
 		history: data.history.map((history) => ({
 			name: history.name,
 			content: history.content,
diff --git a/src/lib/types/session.ts b/src/lib/types/session.ts
index 597c1d5..cfc9bb7 100644
--- a/src/lib/types/session.ts
+++ b/src/lib/types/session.ts
@@ -9,18 +9,29 @@ export interface FirestoreSession {
 	title: string;
 	createdAt: Timestamp;
 	status: 'draft' | 'waiting' | 'active' | 'ended';
+	stage: 'grouping' | 'individual' | 'group' | 'ended';
 	tempIdExpiry: Timestamp | null;
 	goal: string;
 	subQuestions: string[];
-	resourcesIds: string[];
+	resourceIds: string[];
 	participants: {
 		[userId: string]: {
 			name: string;
 			groupId: string | null;
+			groupName: string | null;
 			joinedAt: Timestamp;
 		};
 	};
-	stage: 'grouping' | 'individual' | 'group' | 'ended';
+	groups: {
+		[groupId: string]: {
+			groupName: string;
+			members: {
+				[userId: string]: {
+					name: string;
+				};
+			};
+		};
+	};
 }
 
 // Client-side data structure (serializable)
@@ -32,10 +43,11 @@ export interface Session {
 	title: string;
 	createdAt: string;
 	status: 'draft' | 'waiting' | 'active' | 'ended';
+	stage: 'grouping' | 'individual' | 'group' | 'ended';
 	tempIdExpiry: string | null;
 	goal: string;
 	subQuestions: string[];
-	resourcesIds: string[];
+	resourceIds: string[];
 	participants: {
 		[userId: string]: {
 			name: string;
@@ -43,7 +55,16 @@ export interface Session {
 			joinedAt: string;
 		};
 	};
-	stage: 'grouping' | 'individual' | 'group' | 'ended';
+	groups: {
+		[groupId: string]: {
+			groupName: string;
+			members: {
+				[userId: string]: {
+					name: string;
+				};
+			};
+		};
+	};
 }
 
 // convert Firestore data to client-side data
@@ -56,20 +77,37 @@ export function convertFirestoreSession(data: FirestoreSession): Session {
 		title: data.title,
 		createdAt: data.createdAt.toDate().toISOString(),
 		status: data.status,
+		stage: data.stage,
 		tempIdExpiry: data.tempIdExpiry ? data.tempIdExpiry.toDate().toISOString() : null,
 		goal: data.goal,
 		subQuestions: data.subQuestions,
-		resourcesIds: data.resourcesIds,
+		resourceIds: data.resourceIds,
 		participants: Object.fromEntries(
 			Object.entries(data.participants).map(([userId, participant]) => [
 				userId,
 				{
 					name: participant.name,
 					groupId: participant.groupId,
+					groupName: participant.groupName,
 					joinedAt: participant.joinedAt.toDate().toISOString()
 				}
 			])
 		),
-		stage: data.stage
+		groups: Object.fromEntries(
+			Object.entries(data.groups).map(([groupId, group]) => [
+				groupId,
+				{
+					groupName: group.groupName,
+					members: Object.fromEntries(
+						Object.entries(group.members).map(([userId, member]) => [
+							userId,
+							{
+								name: member.name
+							}
+						])
+					)
+				}
+			])
+		)
 	};
 }
diff --git a/src/lib/types/speech.ts b/src/lib/types/speech.ts
deleted file mode 100644
index d2c20a8..0000000
--- a/src/lib/types/speech.ts
+++ /dev/null
@@ -1,19 +0,0 @@
-export interface FirestoreSpeech {
-	speechId: string;
-	fileId: string;
-	transcription: string;
-}
-
-export interface Speech {
-	speechId: string;
-	fileId: string;
-	transcription: string;
-}
-
-export function convertFirestoreSpeech(data: FirestoreSpeech): Speech {
-	return {
-		speechId: data.speechId,
-		fileId: data.fileId,
-		transcription: data.transcription
-	};
-}
diff --git a/src/routes/session/[id]/+page.svelte b/src/routes/session/[id]/+page.svelte
index f5c59aa..2c77189 100644
--- a/src/routes/session/[id]/+page.svelte
+++ b/src/routes/session/[id]/+page.svelte
@@ -8,7 +8,6 @@
 		Trash2,
 		Play,
 		Users,
-		Link,
 		FileText,
 		Clock,
 		Pencil,
@@ -213,24 +212,9 @@
 						<div class="space-y-3">
 							{#each Object.entries(session.resources) as [, resource]}
 								<div class="flex items-start gap-3 rounded-lg border p-3">
-									{#if resource.type === 'link'}
-										<Link size={20} class="mt-1 text-blue-600" />
-									{:else}
-										<FileText size={20} class="mt-1 text-gray-600" />
-									{/if}
+									<FileText size={20} class="mt-1 text-gray-600" />
 									<div>
-										{#if resource.type === 'link'}
-											<a
-												href={resource.content}
-												target="_blank"
-												rel="noopener noreferrer"
-												class="text-blue-600 hover:underline"
-											>
-												{resource.content}
-											</a>
-										{:else}
-											<p>{resource.content}</p>
-										{/if}
+										<p>{resource.text}</p>
 										<p class="mt-1 text-sm text-gray-500">
 											Added {formatDate(resource.addedAt)}
 										</p>
diff --git a/src/routes/session/[id]/participant/+page.server.ts b/src/routes/session/[id]/participant/+page.server.ts
index a15f1dd..56f4ab4 100644
--- a/src/routes/session/[id]/participant/+page.server.ts
+++ b/src/routes/session/[id]/participant/+page.server.ts
@@ -1,4 +1,12 @@
+import { env } from '$env/dynamic/private';
 import { adminDb } from '$lib/server/firebase';
+import { chatWithLLMByDocs } from '$lib/server/llm';
+import { parsePdf2Text } from '$lib/server/parse';
+import { transcribe } from '$lib/stt/core';
+import {
+	convertFirestoreIndividualDiscussion,
+	type FirestoreIndividualDiscussion
+} from '$lib/types/IndividualDiscussion';
 import type { FirestoreSession } from '$lib/types/session';
 import { convertFirestoreSession } from '$lib/types/session';
 import { error, fail, redirect } from '@sveltejs/kit';
@@ -60,5 +68,91 @@ export const actions = {
 		});
 
 		return { success: true, groupId };
+	},
+
+	startIndividualStage: async ({ locals, params }) => {
+		const sessionId = params.id;
+		const sessionRef = adminDb.collection('sessions').doc(sessionId);
+		const sessionData = (await sessionRef.get()).data() as FirestoreSession;
+		if (sessionData.hostId != locals.user?.uid) {
+			throw redirect(401, 'Unauthorized');
+		}
+
+		const resourcesTexts = [];
+		// parse pdf files to text
+		for (const resourceId of sessionData.resourceIds) {
+			const resourceRef = adminDb.collection('resources').doc(resourceId);
+			const resourceData = (await resourceRef.get()).data();
+			const text = await parsePdf2Text(resourceData?.fileId);
+			resourcesTexts.push(text);
+		}
+
+		// create conversation for each participants
+		for (const participantId in sessionData.participants) {
+			const individualDiscussionRef = adminDb.collection('individualDiscussion').doc();
+			await individualDiscussionRef.set({
+				userId: participantId,
+				sessionId: sessionId,
+				groupId: sessionData.participants[participantId].groupId,
+				goal: sessionData.goal,
+				subQuestions: sessionData.subQuestions,
+				resourcesTexts: resourcesTexts,
+				history: [],
+				summary: ''
+			});
+		}
+
+		// set session stage to individual
+		await sessionRef.update({ stage: 'individual' });
+
+		return { success: true };
+	},
+
+	sendConversation: async ({ request, locals, params }) => {
+		if (!locals.user) {
+			throw error(401, 'Unauthorized');
+		}
+		const { speech } = await request.json();
+		const userId = locals.user.uid;
+		const sessionId = params.id;
+
+		const fileId = 'Unknown file id'; // TODO: get file id from the file upload
+		const text = await transcribe(speech, env.HUGGINGFACE_TOKEN);
+
+		const individualDiscussionRef = adminDb
+			.collection('individualDiscussion')
+			.where('userId', '==', userId)
+			.where('sessionId', '==', sessionId);
+		const individualDiscussionData = (
+			await individualDiscussionRef.get()
+		).docs[0].data() as FirestoreIndividualDiscussion;
+
+		if (!individualDiscussionData) {
+			throw error(404, 'Individual discussion not found');
+		}
+
+		const { history, goal, subQuestions, resourcesTexts } =
+			convertFirestoreIndividualDiscussion(individualDiscussionData);
+
+		history.push({
+			role: 'user',
+			fileId: fileId,
+			content: text,
+			timestamp: new Date().toISOString()
+		});
+
+		const response = await chatWithLLMByDocs(history, goal, subQuestions, resourcesTexts);
+		if (!response.success) {
+			throw error(500, response.error);
+		}
+
+		history.push({
+			role: 'user',
+			fileId: null,
+			content: response.message,
+			timestamp: new Date().toISOString()
+		});
+
+		return { success: true };
 	}
 } satisfies Actions;
diff --git a/src/routes/session/[id]/participant/+page.svelte b/src/routes/session/[id]/participant/+page.svelte
index 63571fb..7093966 100644
--- a/src/routes/session/[id]/participant/+page.svelte
+++ b/src/routes/session/[id]/participant/+page.svelte
@@ -1,6 +1,5 @@
 <script lang="ts">
 	import { enhance } from '$app/forms';
-	import QRCode from '$lib/components/QRCode.svelte';
 	import QrScanner from '$lib/components/QrScanner.svelte';
 	import { db } from '$lib/firebase';
 	import type { FirestoreSession } from '$lib/types/session';
@@ -16,12 +15,7 @@
 
 	// Find user's current group
 	$effect(() => {
-		for (const [groupId, group] of Object.entries(session.groups || {})) {
-			if (user.uid in group.members) {
-				currentGroupId = groupId;
-				break;
-			}
-		}
+		currentGroupId = session.participants[user.uid]?.groupId || null;
 	});
 
 	function handleScanGroup(groupId: string) {
@@ -134,28 +128,23 @@
 			<div class="rounded-lg border p-6">
 				<h3 class="mb-4 text-lg font-semibold">Your Group</h3>
 				<div class="space-y-4">
-					<p>Group Name: {session.groups[currentGroupId].name}</p>
+					<p>Group Name: {session.groups[currentGroupId].groupName}</p>
 					<div>
 						<p class="mb-2 font-medium">Members:</p>
 						<ul class="space-y-2">
-							{#each Object.entries(session.groups[currentGroupId].members) as [memberId, member]}
+							{#each Object.values(session.groups[currentGroupId].members) as member}
 								<li class="flex items-center gap-2">
 									<span>{member.name}</span>
-									{#if memberId === session.groups[currentGroupId].leaderId}
-										<span class="rounded-full bg-blue-100 px-2 py-0.5 text-xs text-blue-600">
-											Leader
-										</span>
-									{/if}
 								</li>
 							{/each}
 						</ul>
 					</div>
-					{#if user.uid === session.groups[currentGroupId].leaderId}
+					<!-- {#if user.uid === session.groups[currentGroupId].leaderId}
 						<div>
 							<p class="mb-2">Group QR Code:</p>
 							<QRCode value={currentGroupId} />
 						</div>
-					{/if}
+					{/if} -->
 				</div>
 			</div>
 		{/if}