How do you add songs to Frets on Fire

If you mean "Cannon Rock: Frets on Fire", you have to download it and set it as a custom onto your Guitar Hero game (I'm not so sure how to do it myself, but I've heard of it. You're on your own to find the site.) This what you do for the mac. You download the song, if it's a "rar" file, use UnRarX if you have it, so you can covert it to a folder. Right click frets on fire in your dock, or on your desktop, click "Show Package Contents" . Then double click "contents" then double click "Resources" then double click "Data" then scroll down to the "songs" folder. Say you downloaded Revolution Deathsquad by Dragonforce. Drag the "Revolution Deathsquad" song folder into the "songs" folder. click the red X in the circle at the top, and start Frets On Fire. Have fun! But, there's a catch. sometimes the song folder you downloaded won't have the right items in it. Or it won't have enough items in it. It's happened to me before. So, as I said before, have fun!