Test the wires to make sure that the facility is shut off. Hold one terminal on the voltmeter to the black wire within the wall box. Touch the opposite terminal to the white wire. The meter on the voltmeter should remain still or register “0.” If not, you haven’t turned off the correct circuit.
If there is a light switch currently within the wall box, remove it by unscrewing the fasteners at the highest and the bottom holding it in place in the box. Pull the switch out of the box. Unscrew the wires from the terminals on the side.