Hello Ananya Verma, I think you are late for register because as per the instructions given on the sih website are the last date for idea submission is 10 feb of 2020 and for participating in event will be declare by your college because per college there are only 4 or 5 teams are allowed so please confirm it ones at your college and for more information you can visit FAQ (https://www.sih.gov.in/faqs#:~:text=b)%20SPOC%20registration%20will%20start,will%20be%2010th%20February%202020.) and the main website of sih is SIH (https://www.sih.gov.in/)

hope it is helpful for you :)