I don't know anything about the course but registration is pretty straight foward.
Appart from the main university registration that everyone has to do (lots of queuing and form filling), you will have somekind of registration for the course by the people who run it. This is useful as you get to meet the other people that will take the course with you. There are plenty of talks about the department and very likely a drinks and nibbles thing where you get to meet other people in the department.
Sheffield is lovely of course, are you staying in halls or private?