Get a volt meter and start the generator after you have disconnected from the house power. Check the outlet in the compartment that you were told to plug into for generator power. If there isn't power in that outlet check any other outlet in the compartment if none of them have power then the generator has a problem. Did you see the previous owner plug into the generator outlet? See if you can find a copy of the owners manual for the generator and see if it tells you where the circuit breaker for the generator is located. Might be the circuit breaker has opened and needs to be reset.