u have to find it first and to slide u must hold down and press z (a for controller, u must have the as far as i can remember u must first have the speed boots, jump boots, and bommerang before u find u should enter a room that has a laser blocking the room below and a red circle in it too, hit it with ur boomerang and it will break and the laser disappers giving u acecss to the room below, hope this helped