As other have already stated, you don't have an automatic transfer switch that would switch between shore power and the generator. Instead, to use the generator you need to plug the end of the shore power cord into the generator socket inside your electrical compartment.
Here's the Body, 110 Volt Wiring Diagram
for your coach. At the top of the last page you'll see an illustration of the generator power socket and the power cord to plug into it. Here's the Body, 110 Volt Wiring Installation
for your coach as well. In detail DA
on the upper right corner of page 5 you'll see the location of the generator socket.
Just fyi, here's the 2000 Spirit Brochur
e as well.