Your admission is complete and by that it implies the counselling is over and you  might also have submitted the fees. Next, you'll be called for the medical examination (it can also be done when you go for document verification) where you'll be tested for colour blindness etc. After this there is nothing much for you to do, there is no need to shop for books beforehand (teachers will suggest whats best). Relax, and catch up on what you've missed while preparing hard.