Hello Saurabh.
You should have selected colleges during counselling as per your rank and marks. But I think you have not taken it serious during choice locking. If your rank is not good enough then you should have selected all NIT gfti iiits and few private colleges. But in case you have done something wrong then only option is to choose float option till last don't  worry you will get a college till end.
Ok
Good luck..