On my fun finder, the batter switch is a silver knob that pushes in or pulls out.
In is off or disconnected from 12 volt battery power.
Out is on or connected to 12 volt battery power.
I have mine pulled out all the time so the brakes will work should the camper ever become disconnected from the tow vehicle, the emergency lanyard of pulled out of the breakaway switch and the trailer brakes will activate.
Personally - I don't understand a reason to have the 12 volt power switched to being with.
2012 Fun Finder XT 276 Toy Hauler & Harley Davidson Ultra Classic with Condor wheel chock
2014 Dodge Ram 2500 AT 4X4 Crew Cab 6.4 L Hemi, 373 gears, tow package, Rambox option, Revolver X2 tonneau cover, Equal-I-zer anti-sway hitch.