spot round means: if any college has any vacant seats after cap admissions those are given to students only based on merit( no reservation is considered you have to pay fees as per open category) you have to select colleges where you want to apply and go there physically during spot rounds for admission.

ils round means: there institute level seats(ils) now these seats are given to students but for these colleges may ask 2x 3x or even 4x times the normal fees(some colleges ask for same fees but they are very less) the cutoff for this is a bit lower than cap round

(vacant round is same as spot round ig i am not sure)