"This Apple ID has not yet been used with the iTunes Store."

Alright so I'm not entirely sure what kind of mac I have I just know it's not a pro. Anyways, I'm trying to hook up my itunes with the Apple TV but first I know I have to get into the cloud blah blah blah. I'm trying to sign into itunes, but the above message just keeps popping up, it's infuriating. If anyone could tell me how to set up my Apple ID so that I can use the store, that would be fantastic. Thank you.