Welcome to iRV2.
When the gen set is running ; does the clock on the micro wave come on
, Is that why you're asking about micro wave only power ?
If your RV came without an ATS ( Auto Transfer Switch ) there should be an outlet for the shore power cable to plug into , in the cable bay.
If you can follow the shore power cable and the gen set power cable to a common box , then that box would be an ATS, and if functioning properly , the ATS should activate after the gen set has been running for about 90 seconds.
The delay is to allow the gen set to warm up and stabilize power output.