doc: updated usage section in readme

Author: KittyChiu

README.md

@@ -4,9 +4,59 @@ A composite Action for packaging and uploading artifact that can be deployed to
 
 ## Usage
 
-See [action.yml](action.yml)
+See [action.yml](action.yml) for the various `inputs` this action supports (or [below](#inputs-📥)).
+
+We recommend this action to be used in the build job:
+
+```yaml
+jobs:
+  # Build job
+  build:
+
+    # Specify runner +  build & upload the static files as an artifact
+    runs-on: ubuntu-latest
+    steps:
+			- name: Build static files
+				id: build
+				run: |
+					# <Not provided for brevity>
+					# At a minimum this step should build the static files of your site
+					# <Not provided for brevity>
+
+      - name:  Upload static files as artifact
+        id: deployment
+        uses: actions/upload-pages-artifact@v3 # or specific "vX.X.X" version tag for this action
+				with:
+					path: build_outputs_folder/
+
+  # Deployment job
+  deploy:
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4
+
+```
+
+### Inputs 📥
+
+| Input            | Required? | Default                 | Description                                        |
+| ---------------- | --------- | ----------------------- | -------------------------------------------------- |
+| `name`           | `false`   | `github-pages`          | Artifact name                                      |
+| `path`           | `true`    | `_site/` | Path of the directory containing the static assets |
+| `retention-days` | `false`   | `1`                     | Duration after which artifact will expire in days  |
+
+### Outputs 📤
+
+| Output        | Description                              |
+| ------------- | ---------------------------------------- |
+| `artifact_id` | The ID of the artifact that was uploaded |
 
-<!-- TODO: document custom workflow -->
 
 ## Artifact validation