When I hit my breaks to slow at a light I get a Loud clunking noise on 2006 Ford Mustang

The noise comes from my rear right side (tire maybe) I just put new tires on it 1 month ago(tire pressure sensor light still hasn't gone off)

Asked by for the 2006 Ford Mustang
Possible disc brake pad(s) hardware missing or improperly installed. Also possible, the spare tire needs more air, have 'ALL' tires checked for PROPER psi!
I'll have them check the breaks thank you! I didn't even think about the spare I'll have to check on that too, all my other tires are at proper psi.