Just got an iphone and my apple id won't work?

I just got an iphone 5 (finally) but now my apple id won't work and the lady at the store said I have to register it on the apple website? I don't know how to do that though. Can someone help me out?

I see you may need to create an apple id first try creating one at https://appleid.apple.com/...ple.com/us then entering the login information on your iphone.