Propane smells quite a lot. It there is no smell coming from a stove top burner immediately, then hold a lit bbq starter over the burner, and turn it on for 15 seconds with the flame going on the starter. If any gas shows up at all, the flame will light up the extra propane.
Other than that.. see above. If you find the valve shut off then use the lit bbq lighter stick again on the stove to fill the lines before trying other things.
And, then next thing to check, and I was recently called over to troubleshoot this one.. they had not taken the hot water tank out of bypass, so no water was in the hot water tank at all. Be sure your valves for the water inlet and outlet are open, and the bypass valve is shut.
