No dumb questions here. Mine runs on either propane or electric (120 volt when plugged in to campground source) and switches automatically. I am very glad for the automatic switch, as I know I would never remember to do it manually.
Even when it runs on propane, it does require a tiny bit of 12v power, which is supplied by the house batteries.
And, by the way, it took me 6 months to figure out how the 12v batteries got charged by the 120v outside hookup through the converter, and then ran all the lights. I kept thinking the lights in my motorhome also switched over to 120v, which is impossible!! My inverter is under my bed in a wooden box, and I flipped the breaker to turn it off once because I couldn't figure out what the noise was coming from. Then when my batteries ran down and my lights got dim, someone helped me figure it out.