If you are satisfied with the allotted seat in round 1 of josaa counselling then you should choose freeze option and take out the provisional seat allotment letter and procced for admission according to the institute guidelines which should be available ion the institutes website, if you are not satisfied then choose float option and wait for desired preference until allotted if you are satisfied with college but not with branch then choose slide as the you will be allotted the institute but you will be eligible for branch upgradation.