doc: improve sample.env documentation

Author: VincentHardouin

sample.env

@@ -14,12 +14,18 @@ UCPA_MAIL_RECEIVER_IMAP_USER=
 UCPA_MAIL_RECEIVER_IMAP_PASSWORD=
 UCPA_MAIL_RECEIVER_IMAP_SEARCH_QUERY=
 
+# The area id can be found in the network calls on your center's booking page.
+# Default: Paris : area_1639603560_9977f290-5ded-11ec-96d0-03e553c50e2f
 UCPA_AREA_ID=area_1639603560_9977f290-5ded-11ec-96d0-03e553c50e2f
 
-FORM_RESPONSE='{ "club": "6", "firstName": "", "lastName": "", "", "tel": "" }'
+# The club number corresponds to the position of your center in the select of this form : https://sphinx.ucpa.com/surveyserver/s/ucpa/CONTREMARQUE/Gymlib.htm
+# Default: Paris: 6
+FORM_RESPONSE='{ "club": "6", "firstName": "", "lastName": "", "email": "", "tel": "" }'
 FORM_SUBMIT_ENABLED=true
 
-CRON_TIME='0 */5 * * * *'
+CRON_TIME='0 */10 * * * *'
+
+# Your preferred slots should be ordered by day and slot preference; not every day has to be present.
 TIME_SLOTS_PREFERENCES='{
     "sun": [
         "17h00",
@@ -45,4 +51,7 @@ TIME_SLOTS_PREFERENCES='{
 }'
 
 CALENDAR_NAME=ucpa
+
+# Generate a new uuid to make the calendar url unpredictable
+# Ex: node --eval "console.log(require('crypto').randomUUID());"
 CALENDAR_ID=5f67a0f9-3c63-4be5-b86a-c064ebcea491