Ardurover on lawn tractor steering solution

Hey there, I’m trying to build an autonomous lawn tractor. But a solution for the steering seems to be thought to find.
My best guess would be to build something similar to this https://youtu.be/JyIkXSQGX_8?list=LL&t=164
but with a used hoverbord motor and a gt2 6mm timing belt pulley
https://www.printables.com/de/model/568306-120-tooth-gt2-pulley-for-65-hoverboard-motor
how do i control the motor to only turn a certain amount?

feedback and ideas are welcomed