You are able to purchase the solenoid activated thermostat style controller for these AC units.
B-: 12v Ground. Required for solenoid activation. There is a plain white wire with the red and white wires coming from the furnace at the factory thermostat location which can be tied to this wire. Or any metal ground would work.
GH: Fan high lead
GL: Fan low lead
The freeze terminals go to an included sensor, I'm not exactly sure what it does but I installed it the same place where the factory one was, up in the plenum.