Add instructions for registering the act_runner in README

README.md

@@ -33,6 +33,24 @@ curl -fSSL https://get-act.tk2s.org | sudo bash
 - The script will update an existing installation if a newer version is available.
 - You may need network access to `gitea.com` to retrieve release metadata.
 
+### Register the runner
+
+Replace placeholders and run:
+
+```bash
+act_runner register \
+  --config /etc/act_runner/config.yaml \
+  --instance https://your-gitea.example.com \
+  --token <REGISTRATION_TOKEN> \
+  --no-interactive
+```
+
+Then start (or restart) the service:
+
+```bash
+systemctl restart act-runner
+```
+
 ### Uninstall
 
 ```bash