Setting up ID on new phone

I'm helping someone set up their ID on their phone because it's new. She has 7 days before it locks her out. We've gone through the steps all the way through and once we do it takes us back the the Apple ID sign-in. But then it won't let us in because the password is wrong and it shouldn't be. Do we have to re-set the password or something? I'm running out of ideas of what we could do.