No power at all, help with wiring please

Follow the blue circled wire through the bulkhead connector and up to the amp meter, as that is your power supply into the cabin.
If it's not 12v all the way to the amp meter you probably found your problem.

Also check both terminals of the amp meter.
The red wire goes into the amp meter and a large black one goes out of it.
If the red wire on the amp meter has power but the black one does not, it's a blown amp meter and no power can get to anything else.

The two wires on the back of the amp meter can be connected together to bypass the amp meter all together.