I'm looking at purchasing the LG G4 from Bestbuy.com. My carrier is AT&T. I like Bestbuy because you get the $100 gift card. Though I'm not sure how this process actually works. Do you give BestBuy your ATT account information? When they ship the phone to you, do you still have to go to an ATT store to get it activated and/or get a sim card? Or is that all done online during checkout?