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Post make and model of the refer. There is many different models of refers so the model is important. Model number could be on the inside door frame or in the outside refer access.
Yes, there should be a cap on the water fill. A rubber plug would work, but cap twists a bout 1/8-1/4 turn to hold in place.
Most ovens have a Pilot. Turn the knob to pilot. Use long lighter to light the pilot. Some you can remove the shelf just above the burner and pilot location so you can see what is there and where to hold lighter. This is just to get familiar with the oven, not for use.
The 40 amp unit should be the converter. There should be some 120 volt circuit breakers. Next to the breakers should be a small metal plate that covers the 12 volt DC fuses.
