Take off the nuts from the wheels.
Turn the tool anticlockwise until the nut comes off after placing the tool over the nut.
Detach the wheels from their bolts.
Replace these old wheels with new ones.
Return the nuts on the bolts and flat end.
Rotate it clockwise and fasten the nuts.
Notice that don’t tighten the nuts too much. Use your fingers to spin each wheel freely. If it doesn’t spin or is jerky when spinning, the nuts need to be loosened.