That probably won’t power your whole house—too small a genset. You should call an electrician.
I have a Generac 11KW. The only thing it won’t run is the AC and water heater at the same time. Furnace is propane as is the stove. Forget about running an electric furnace with it.
I wired the Transfer box in myself. Everything is color coded. On Generac you just wire whatever you want tor run on the genny through the Transfer box bypassing the main box. When the power goes out for 60 seconds the genny fires up and takes over. Main thing needed is a Positive Disconnect from house main.
Hie an electrician if you don’t know how to do it properly.
I used to power my entire 2400 sq ft house with a 5k genset. 12,500 watts is way more than needed to run an entire house.