There's nothing stupid about this. Mains electrical is serious business, and is a craft entirely separate from EE. (No offense but nobody thinks putting gas in their weedwacker qualifies them to drive a gasoline truck.) So when dealing with mains electrical, bring your best game, a good "homeowner fix-it" guidebook, and a willingness to think different - because everything is different!
While there is much good advice here on how to disable the generator mechanically, I would also look for a way to disconnect it electrically. For instance, a proper generator interlock prevents both utility supply and generator from both being turned on at the same time -- but does allow both to be turned off. E.G. in this dog-simple example: Both supply-main breakers are faced opposite: inward is on. Left breaker is off, right is on, and the interlock allows the right one to be turned off.
Speaking of that, this is also a good time to make sure that the generator is installed to Code. A huge number of generators aren't.