The cable is attached to the throttle body by a black plastic cable nut thing. Unscrew this and you will see a spring and the plunger (should come out with the cable nut thing). Remove the cable end from the plunger and pull it through. Return the plunger and spring back to the throttle body and screw the black cap back on.
You will need to move one or two parts to gain easy access to the throttle boby.
The cable is attached to the frame from memory at two points just with the cable ties.
Remove the 4 screws on the bottom of the start, hi/low assy on the bars. Remove the cable from the lever and the lever from the assembly. I cant remenber if you need to undo anything to remove the cable from the assembly. Refit to bars and reattach the rubber boot.
This is from memory and unfortunately I dont have the bike here to take pics of.
My bike was already in pieces when I did this so i dont know if you need to remove any plastics or anything.