Module: Media
Media Step By Step is a good article to review.

Click
Add to insert a media schedule(s) for the Ad Copy, and the "edit media schedule data" window will pop up:

This allows you to conveniently create a media schedule for the ad copy that you are working in, rather than having to navigate away from ad copy module to set it up and then attach it. Please refer to the Media Schedule article for details on the schedule data.