Fill the form through acsir and there are two rounds of interview followed by pi interaction where you have to select you supervisor under which you complete your PhD. Overall nice experience supportive people the helps you during interview and give hints

3 round interview process- First round was screening test(written). The second round was personal interview->technical biotechnology, biology questions. If you had prepared for GATE/NET or any national level entrance test, you should be able to answer. The final round was mostly HR based personal questions. Finally, if you're selected you are allowed to have one-to-one interactions with scientists and decide whom to join.