I have a duel furnace and I want to run just the electric heat pump on it. How do I do that?

Your thermostat should be a two stage, heat pump first, and propane second. You can shut off the gas to the furnace... BUT when the heat pump goes into defrost cycle you will be cooling the house... not such a good idea. If the heat pump keeps up with the demand the propane should only come on during the defrost cycle.