Need to get hooks when someone completes a course


I am making some modifications to the plugin and wanted my code to be triggered when a new course was made, and when one course was completed by the user.

What I am trying to do here, is make a compulsory gap of 7days between 2 different courses. I was planning to run WP_CRON to check that and needed a hook so my code could know when the course was done. Any better way to do this?

I will need a hook/signal that a course has been created, I will also need to hook/signal when the user just completed a course. Please let me know.