Why are there two grounding bars in my breaker box?
The isolated bar is intended for Neutral.
If, like many generators, yours has ground and neutral bonded inside the generator, your generator neutral and all neutral wires go to the isolated bar, and the ground wires go to the one connected to the box.
That also sets you up properly for a &quot;shore power&quot; input.
Your hot feed either goes to one of the line inputs and you only use that half of the breaker spaces, or you connect your hot feed to both line inputs with a jumper, since this is 120V only, so there won't be any 240V dual-breakers. The former leaves the ability to connect to shore power (or a larger generator) &quot;properly&quot; and the latter does not (but will work if you are only plugging into a 120V-only shore connection.)