There at least a thousand threads that explain it
on 50 amp you have L1-N-L2
on 20 or 30 the adapter you use to connect to the outlet connects L-1 and L-2
So you have HOt-Neutral-Same hot
When you wire the Go-Power you do not wire it in the shore feed.
Shore---Main breaker box--30 amp breakers---Go-power---Sub box--Selected loads
Selected loads are TV. Microwave. GFCI chain and possibly the fridge and selected other outlets. You do not use the inverter for the water heater. OR air conditioners. and you will most likely disconnect the converter (IN my case I did not but that's my choice. and one very nice converter)
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times