Site Registration

Hi thanks for viewing.

I’m wondering how i could set up a registration form on my site. I’m selling tickets to an event and want that purchase to allow users to buy more tickets for classes within the event. Obviously i dont want them to be able to book classes without having bought a ticket so was thinking of registering users as part of the initial purchase process, registration could only be completed after confirmation from paypal.

Is this possible. Even without the paypal stipulation how does one go about registering a user?

Many Thanks

Frank