4, Remove unit back plate by releasing two tabs at the bottom with a narrow screwdriver blade, and pull away. {Diagram B} 5. For WALL OR CEILING MOUNTING, place screws through appropriate keyhole slots and tighten. Be sure to orient the back plate, so the test switch faces the bottom, or desired direction, if ceiling mounted. FOR MOUNTING TO A JUNCTION BOX, Complete wiring connections as per step 6, and secure to box by removing appropriate knockouts in back plate.