hey,

to get admission in any of the IITs and NITs you are first required to fill the application form of JEE mains and after qualifying JEE mains fill the  form of JEE advanced , the application form of JEE mains 2020 was out from 7 february to march 12, 2020 and aspirants were given second chance also to fill the application form of same by again opening the application form window from May 19, to 24 , 2020

i  guess you have missed this time , you may try next year.

all the best!