Under the front of the sofa you should see a door, hinged at the bottom. Open that door. Then left to right you've got the real main disconnect (the remote disconnect operates this one), the 12vDC house fuses, the 120vAC circuit breakers, and the inverter/charger.
You should have additional "house" fuses in the pedestal under the driver's seat, for things that were added by Airstream but powered off the chassis systemó such as your retractable step by the sliding door.
I thought getting old would take longer!