Turn the propane tank cylinder valve clockwise until it tightens all the way to shut it off. Turn the fireplace gas control valves off.
Route the gas hose line under a carpet or out of the way to eliminate the risk of tripping over it.
Check the fireplace's propane gas hose lines for physical damage. Hand tighten any connectors that are loose.
Hold the pressure regulator up to the cylinder valve of the propane tank. Insert the pressure regulator nipple so the small probe located inside of it is centered on the valve. Hand tighten the nut of the pressure regulator nipple onto the propane cylinder valve.
Turn on the propane cylinder valve and the fireplace gas control valves.