Turn off the breaker in the circuit breaker box to the area where the lantern will be installed. If the breaker switches inside the box are not labeled, it will take some experimenting to locate the proper breaker. Make sure the power to the wiring where you'll be working is off before starting to install the lantern.
Assemble the wall lantern if needed once it is out of the box. Follow the instructions included with the lantern.
Prepare the wires in the receptacle box on the wall by stripping the plastic coating off the ends with wire strippers, if needed. Leave at least one inch of each wire bare.
Match the wires from the lantern to the wires in the receptacle box. The white wire attaches to the white wire, the black wire to the black and the green wire to the bare copper wire. Push the two matching wire ends into a wire connector and twist it down until secured. After all the wires are connected, coil them into the receptacle box.
Secure the wall lantern to the side of the house with screws provided in the packaging.
Apply a thin bead of clear silicone caulk around the edge of the lantern where it touches the wall. This weatherproofs the lantern and keeps out moisture. Turn the power back on at the breaker box, then turn on the lantern at the wall switch to test the connection.