I've never had a heat pump nor have I ever dealt with one. Hopefully, someone will come along and help you out. Have you tried looking for your problem on YouTube or Google?
heat pumps is like a heating unit the uses compressor.
it uses reverse valve to move refrigerant to the indoor coils first, then outdoor coils.
indoor coils becomes the condenser coils and outdoor coils become the evaporator coils.
the indoor fan and coils sucks the cold air though the coils giving u warm air.
the outdoor fan blows the cold air out from the outdoor coils.