Once you're done at Diagon Alley, you have to be sorted. Unfortunately, the Sorting Hat doesn't choose your house so you have to pick one yourself.
Next, you get a dorm, which you can either get randomly or you can choose to join one if your friends are also enrolled.
Hogwarts Is Here takes things pretty seriously. Each course lasts nine weeks and you have to complete tests and a final exam in order to pass.
But it's not all books and homework. In mid-April you can apply to join the school paper, the Daily Owl.
Anyway, the first class I enrolled in? Defense Against the Dark Arts. Naturally.
Upon enrolling you are able to access your syllabus:
The first assignment is an introductory essay for the professor to see how much you know about the Dark Arts and what you'd like to learn.
But you can't start your next assignment until you finish your first. And so on and so forth. So make sure to do your work in a timely manner! If not...