Attach wheel to the hanger and lower down motor to prepare gear meshing.

If wheel gear one side is pulled in or further than other sides check wheel hub bolts probably one bolt is more tighten than others or otherwise

If wheel gear is more inside than motor gear use washers provided to pull wheel gear away from baseplate

Loosen up motor bolts so that motor gear would press wheel gear.

Use sheet of paper to drive it through wheel gear and motor gear. Spin wheel to push paper through the gears

After meshing is good tighten motor bolts