Hi , Debnath .

First of all you do not need to attend the institute after the 1st round which you are alloted but you need to attend the nearest reporting centre . And after 1st round if you choose float option then also there is no need to attend the institute you alloted in further rounds  . You just have to attend the reporting centre and lock your alloted institute if you are ok with that.

If you dont want to join institutes alloted in 2 or 3rd rounds you can just leave and the float continues till the last (7th) round . But the institute alloted in your 7th round is fixed and you must have to join there if you are not willing to participate inspot round .

Hope it helps you .thank you.