As there are only 2 IITs which offer B.Arch program (IIT KHARAGPUR & ROORKEE) so to secure seat in these institutes you will have to clear Architecture Aptitude Test (AAT) and the aspirants who have secured a rank in JEE (Advanced) are eligible to sit for AAT so in order to get a B. Arch course in these two institutions, one has to clear Paper 1 of JEE Main, JEE Advanced and AAT as this is the basic criteria.

Good Luck!!!