There's a circuit breaker on the generator. Check it. If it is on, switch it off and then back on. If it's okay, check your electrical distribution panel (with the breakers and fuses) to be see if you are getting 120 volts to it when the generator is running. (It sounds like you are not.)
Of course, it's possible that your generator is not working properly. If the generator's breaker is on, can you check to see if it's putting out 120 volts when it is running?
We have a 2011 Sunseeker. It has an automatic transfer switch that switches the 120 volt source from shore line to generator when the generator is running. With the automatic transfer switch, you don't have to do anything to run on the generator but start it. I can't say for sure, but yours probably has one, too. (Some models don't have an automatic transfer switch so you have to plug your shore line into a receptacle that is fed from the generator.) The transfer switch could be faulty. Follow your shore line into the coach to find the transfer switch. It will be about half the size of a shoe box, and will have three cables going into it: shore line, feed from generator, and line to the power distribution panel. I think the transfer switch enclosure has the cable entry holes marked as to which cable goes through which hole. If you can locate the transfer switch, plug in the shore line and turn on the breaker that supplies it, then have someone start the generator while you listen to the transfer switch. After the generator has run for a few minutes, the transfer switch should make a "clunk" as it switches from shore power to generator. If you are competent working with 120 volt electricity, see if you have 120 volts coming into it with from the generator.
There are threads in this forum on the transfer switch, as well as problems with no 120 volts when running on the generator. Use the search box at the top of this web page. You may find what you need already posted.
Post back with what you found out, post the generator information that was mentioned in a post above, and someone will probably be able to guide you to the next step.