Gst on sale of a flat ?

Dear Sir,

one of my relative promoting a building and after complition the construction he will sale all the flats. I want to know that is GST levied on sale of flat? If yes what is the rate of GST? Can I claim all the ITC which raised on his purchase bill like cement, iron rod, bricks etc.? How can I pay of labour payment as per the law?

Please guide

Thanks & Regards,

Asim Jana