My question is very big so read it in the additional detail..

See if you have gotten the seat in the first round of the counselling then if you want to go into the allotted institute then you have to pay the certain amount as the security deposit online and this confirms your seat in that college. Now if you do not confirm your admission in the allotted institute then the seat will be treated as vacant and it will be filled in the subsequent rounds. If you participate in the second round of the counselling then your previous seat will automatically will be cancelled and you will be allotted a new seat after the second round. So you need to go carefully as sometimes leaving the seat can be a serious problem as you may not be able to get the seat further.