Last fall we couldn't get our heat working, and a friend's dad said our thermostat needed replaced... turns out the thermostat was fine it was just the fuse on the breaker box (would've saved me all kinds of trouble). I got the heat working with the new thermostat but it wasn't a thermostat designed for a camper. Since winter was upon us we left it at is. Fast forward to spring and the Father comes over to try and help us rewire the old thermostat, but he removed my labels, his nephew came over and got the fan to work, but not the compressor (I'm assuming because there was no cold air) So now I'm trying to install the previous thermostat, but I have no clue on what I'm doing. I've looked up information and either something is actually broken, or I'm not wiring properly. Any help is appreciated, keep in mind I'm clueless about this stuff, so talk to me like a child. Pictures attached for references.

1) thermostat

2) 2 wire harnesses from the ac and furnace

3) AC wiring

4&#5) furnace wiring