Remove the plastic center cap(pry or pull off)
Remove the C-clip from the axal(or snap ring)
Pull off wheel.
Do not loose the little steel key that fits in the slot on the axal and inside the wheel.
To replace:
replace wheel on axal
Line up slot in wheel with grove in axal
Slide in little steel axal key in grove
Replace C-clap or snap ring on axal
Drive off down the road..Thats it