Getting Dometic Heater to run without an AC unit on roof

I guess we better drill down to part numbers:

Here is one option: Dometic Duo-Therm AC 3106996.022 Heat & Cool Relay Control Board

Another via Walmart - Dometic 3316230.000 White Duotherm Single Zone Thermostat with Control Kit

It remains a little unclear if the board or kit will be superior, as in add a thermostat or just add the board.