What should I do to study B.Arch from an IIT?

First you have to appear in both paper 1 and paper 2 of jee main. And have to clear paper 1 and a min. score in paper 2 which is not hard to get. Then you will also have to qualify jee advance after that finally you have to appear for AAT (architecture aptitude test) you need to clear that too. You

as far as my kno, u have to crack jee mains and then jee advanced and then u will be able to sit for AAT(Architecture Aptitude Test), which u need to qualify for the asked purpose.