i just did one recently but on a different engine. here's what worked for me.
1. find the throttle lever
2. start the engine
3. figure out which way the lever goes to open and close
4. if you don't have one - run a throttle rod (close hanger or other type sturdy wire)
5. make sure when the throttle is open there is sturdy resistance (spring(s) that make it return all the way)
6. hook up the cable to the throttle lever and test it out and adjust.
this was not a five minute setup took much longer but it opens and closes without getting hung up.
hope this helps if not there there are much more experienced bikers here if you can hang in there for a bit.