Well, get your throttle "bar/rod" to peddle hooked up, then run a cable (red) to the engine. There are two ways to hook to the engine and you can see by moving the lever (green) Then cut the cable housing the right size and clamp your cable (or hook up) the cable to the throttle/foot peddle "bar/ rod".
Make sense? Your rod/bar should have a return spring at the end near the rear wheel to help the throttle return to idle.