The hospital registration isn't really a big deal. You can just get a form from student affairs once you're here and fill it out. They will probably announce in one of the lectures which forms you all need to hand in.
For anyone worked up from the ragging thread, don't worry too much.
Shifa, in previous years, was pretty bad in those regards. But it has been toned down a lot.
The worst you will have to do on "campus", is either sing or do a small dance. But most of it is light and friendly, and its easy to get along with the seniors.
Make sure to show respect to seniors because otherwise you'll get on their bad side. Nothing wrong with that but you want the seniors to be giving you advice and ragging is an excellent way to get to know them.
The ragging in the hostel is a bit worse but still generally light at Shifa.
Second and third years will be pretty good to you guys. I cant say as much for the guys above that.