Add missing docs for workflows

docs/challenge/online_competition.rst

@@ -39,6 +39,7 @@ To submit your controller to the competition, you need to push your changes to t
 #. Add two new repository secrets:
   * Name: KaggleUsername, Secret: Your Kaggle username
   * Name: KaggleKey, Secret: Your Kaggle API key
+#. Go to your forked repository and click on the "Actions" tab. Enable workflows copied from the forked repository.
 
 Once you've made your changes and are ready to submit, push your updates to the main branch of your forked repository. This action will automatically trigger a GitHub workflow that tests your implementation and submits the results to Kaggle.