step1:- look for suitable college option as per your interest.
step2:- apply when application form is open.
step3:- after getting short listed, go through the further selection process as per college selection guideline.
some college have screening test for admission into PhD. Admission to PhD is done on the basis of score in Masters i.e.PG degree. if you hold good score and done from a recognized college then there is high probability to get an admission. There might be some relaxation for reservation category. Do check it and apply accordingly.
Hope it helps!