Want to automate follow-up emails in Learn

Summary

Has anyone had a program in Learn that had follow-up emails that you used the system to automate?

Content

I'm looking for ideas on automating follow-up emails using Learn.  We have a program that is 3 Learning Plans at the end of the 3rd Learning Plan we need a series of follow-up emails to go out. Ex: 3 days after completion, 1 month after completion, 6 months after completion.

Has anyone found a way to automate such emails? The completion message doesn't give me the option of setting additional or changing the trigger.