A medley is a composition consisting of a blend of multiple songs. Each individual song contained in the medley would be reported on your Copyright License® Report if you made a new copy of it during your assigned reporting period. On your copies, the ownership information should be included under each song, making it easier to search and report each song. This would be true whether you copied the entire song or only a portion of the song.
Using songs that are in the public domain would not be reported.