As the description says you have to 5 star a song in quickplay mode. Take the instrument of your choice and simply start a song you feel confident in playing. The difficulty does NOT matter. You can do it on expert if you want to have some sort of challenge or you can do this on easy if you just want to get this achievement out of the way.
As with instruments and difficulty the type of song you choose doesn't matter either. You can do this on a RB4 song or on any DLC song of your choice.
So in a nutshell:
1. Take whatever instrument you like
2. Take whatever difficulty you want to do this on
3. Choose either a RB4 song or a DLC song.
4. If you do this on expert and get a gold star rating ( an easy song would be Dead Black (Heart of Ice) by Soul Remnants as vocals) you can combine this achievement with the "Well played" achievement and get both after the song ends.
Very easy achievement due to the freedom it offers.
Hope this helps!
Any improvements? Please let me know in the comments below: