You will have to choose which college you want to get through first. Then research on that college and see if its mandatory to write CLAT to get admission in the preferred college. In some colleges CLAT is compulsory while in some other colleges they have their own examinations.

But for now, the registration for CLAT is closed already. It would be better to search for colleges which does not mandate CLAT and apply in those colleges. 

Good luck :)