Here is a schematic of how to install the trimmer pot:
You can use a higher value pot like 1k but the final value is usually around 150 ohms. It's best to use a 10-turn pot but you might get by with a single turn.
Hall Throttle Zero Trimmer.jpg
Here's a picture of an install. You can put tape or heat shrink over the pot when finished.
Throttle smoother.jpg
When adjusting, be sure to have the wheel off the ground as the motor may start without giving throttle. To adjust, start with the pot at zero ohms, then slowly adjust until the motor just starts moving, then back off a little to make sure it stops when you let off the throttle.