I can supply half a brain (all I have, I am told)
The thing down there with the green light is the propane warning alarm. It will make a fuss if the battery voltage gets too low. No fuss, no nothing with no battery at all. It can be reset once you have "12v" again either from battery or converter. Find the user's manual for it.
Look for your battery disconnect switch to make sure it is closed and also check to make sure your converter is supplying 13.6 volts with shore power plugged in. If not, there are things to check on that like its 120v circuit breaker. Make sure the battery is connected right. Red on pos, white on neg. Unless you have black and white--now black is pos and white is still neg. Unless you have red and black! Now red is still pos and black is neg.