Turn the control switch on the gas fireplace to the "Off" position.
Choose a convenient mounting location for the wall switch in accordance with the fireplace manufacturer's instructions. Place the included gang-box template on the wall in the chosen location. Trace the template with a pencil and cut along the traced line with a drywall saw. Slide the gang box into the hole in the wall and tighten the retaining screws with a Phillips screwdriver.
Run a section of two-conductor, low-voltage wire from the single-gang box to the control panel of the gas fireplace.
Strip 1/2 inch of insulation from the ends of the wire. Slide the provided spade connectors onto the stripped ends of the wires in the gas fireplace control panel. Crimp the connectors securely to the wires. Slide the spade connectors onto the spade terminals on the back of the switch in the control panel, or connect them directly to the pigtail wires, if installed.
Turn the wall switch to the "Off" position. Slide the stripped ends of the wires in the single-gang box into the terminals on the back of the wall switch. Press the wires into the terminals until they are secure.
Tuck the wires into the gang box and slide the wall switch into the box. Tighten the retaining screws with a Phillips screwdriver. Place the cover plate over the wall switch and tighten the retaining screws with a flat screwdriver.
Turn the wall switch to the "On" position to activate the fireplace.