You nailed it, The power cord shown in his photo plugs into an outlet, then you can plug something into the power cord (You can't see it in his photo). The cord goes into the black box that switches the AC on/off, via the two wires (pink and white) shown in his photo, These go to the ACC position on his ignition switch.
That TV outlet should be live on generator or shore power. If you want to run the TV off of 12 volts, you either need to install a small inverter, OR, install a TV that operaties off of 12 volts.
I installed a small inverter up front on mine. We use it for laptops, etc while on the road so we don't need to run the generator.
Installing small 400 watt inverter | 2001 Coachmen Mirada 300QB
I also installed a TV that will run on 12 volts. We boondock a lot and I don't like running the genny unless I absolutely have to.
Installing and upgrading TVs | 2001 Coachmen Mirada 300QB