Merge pull request kubernetes-sigs#10449 from pravarag/update-runtime-hook

📖 Update guidelines for runtime hook implementation

Author: k8s-ci-robot

docs/book/src/tasks/experimental-features/runtime-sdk/implement-extensions.md

@@ -358,6 +358,8 @@ implementation documentation.
 
 ## Tips & tricks
 
+Make sure to add the ExtensionConfig object to the YAML manifest used to deploy the runtime extensions (see [Extensionsconfig](#extensionconfig) for more details).
+
 After you implemented and deployed a Runtime Extension you can manually test it by sending HTTP requests.
 This can be for example done via kubectl: