There is a circuit breaker on the generator itself. There isn't usually another fuse or circuit breaker between it and the automatic transfer switch (if you have one). If you don't have a transfer switch, Bobbo's instructions are absolutely right on; you are the transfer switch.
Assuming this is a typical Onan that is installed (and I think other makes are usually similar), you need to open the compartment on the RV and then remove the access panel on the generator itself to get to it. There's generally a start/stop switch there, like the remote one, and maybe a 12V fuse for the generator control circuitry, and the output circuit breaker.