Dear Mursal Amin,

B.Arch courses offered by IIT Roorkee and IIT Kharagpur.

In order to take admission in IITs for B.arch programme you have to appear for JEE Main paper 1 toget qualified for JEE Advanced. 

After clearing JEE Advanced you have to appear for AAT entrance exam. 

The registration process of JEE Advanced AAT 2018 will commence from June 10 to 11, 2018.

To know in detail you can refer below link

https://engineering.careers360.com/articles/jee-advanced-aat

Good Luck!!