DOC: Add usage instructions to readme

README.md

@@ -1,2 +1,47 @@
 # example-service-kueue
-An example Octue Twined data service using Kueue as the service backend.
+
+An example Octue Twined data service using Kubernetes/Kueue as the service backend.
+
+The terraform modules this service depends on are:
+
+- [Octue Twined core](https://github.com/octue/terraform-octue-twined-core)
+- [Octue Twined cluster](https://github.com/octue/terraform-octue-twined-cluster)
+
+## Usage
+
+### Install the client
+
+```shell
+pip install octue
+```
+
+## Usage
+
+### Authenticate with GCP
+
+Download a key for a developer service account and set the `GOOGLE_APPLICATION_CREDENTIALS` environment variable:
+
+```shell
+export GOOGLE_APPLICATION_CREDENTIALS=/path/to/gcp-credentials.json
+```
+
+### Interact with the service
+
+Run the following python code:
+
+```python
+from octue.resources import Child
+
+
+# Point to the data service
+child = Child(
+    id="octue/example-service:0.1.0",
+    backend={"name": "GCPPubSubBackend", "project_name": "octue-sdk-python"},
+)
+
+# Ask a question
+answer, _ = child.ask(input_values={"n_iterations": 5}, timeout=3600)
+
+# Access the output data
+answer
+```