Water Heater

Still learning. Been on 3 trips so far with our Clipper Coachman, all good. Learning and adding things as we go. Last trip we got our heater/furnace going and that was nice on a chilly morning.

That brings me to the water heater. I feel like I'm missing something. Looked at it camp. Then came back and looked at the manual and I can't seem to follow the instructions provided at all. I can't seem to even see what they are talking about. The only buttons/switches are the ones that say 'reset'. And the one I'm pointing to is loose/can move, but doesn't seem like a switch on any sort.

Any help is greatly appreciated! My partner is very much looking forward to cleaning the dishes with warm water, hahaha.

Thanks!