You can check the details below

NITs- You have to appear in JEE Main paper 2 in order to take admission in NITs for B.Arch

IITs- In order to take admission in IITs for B.Arch you have to qualify for JEE Main exam to be eligible to appear for JEE Advanced then you have to clear AAT (Architecture Aptitude Test) entrance exam.

After clearing AAT exam you can take admission in IIT Roorkee and IIT Kharagpur for B.Arch course.

Good Luck!!