It's not a stupid question at all John! The only stupid question is the one you didn't ask!
Sternwheelers normally have their rudders mounted at the rear of the hull, in front of the paddlewheel. Some have rudders behind the wheel, and some use a combination of both....
I've attached an image of towboat Joe's model of the George M Verity, which has rudders in front of, and behind the paddlewheel - I hope that makes things a little clearer?
Regards
Eddy