Can I use Apple ID after computer is setup?

I have a new Mac Pro, being set up from Time Machine on Ext Drive. Everything was going fine, until it asked for Apple ID. Somehow, it's having a problem registering it, even though it's correct with Password. The wheel has been spinning forever, I don't know if I click Set Up Later, just to continue with the process instead of waiting for the wheel to stop spinning, whether I won't be able to register to the existing Apple ID? I want to make sure I'm connected with that ID, for Cloud, ITune, etc. Can I just click Set Up Later to continue setting it up and then come back to that later on, once computer is running, without any issues?