Note: Quickplay is in GHLive not GHTV.
This can either be the same three songs played to completion or three different songs, as long as they are played in Quickplay, and to completion. Enjoy this very easy 10GS :)
I also don't have something else that I wanted to test for this Achievement, so if anyone could let me know down in the comments that'd be wonderful. If playing from "Replay" after you complete the song. Other than going from continue and going back to the same song, also unlocks the achievement. I would assume so, but... anything can happen.