The bottom and back of the wireless controller

Left bumper (2) and right bumper (7): These oblong-shaped controls sit on the top of the controller to the left and right of the USB port. They're used to interact with games, apps, and the Xbox console.

What is RT and RB in controller?

RT = Right trigger = bottom right. RB = Right button = top right. LT = Left trigger = bottom left. LB = Left button = top left. All shoulder buttons ofc.

What button is RT on Xbox?

LT and RT - The left and right triggers. There are the buttons on the top of the controller that are farther away from you. They look like the trigger of a gun (hence the name). On a PlayStation console, these would be L2 and R2.