1. Attach the rear wheels to the frame’s rear axle holes by pressing the black button in the centre of the wheel and then pushing the axle all the way into the axle hole. Release the push button.
2. Check that the wheels are properly attached by pulling/pushing them sideways.
3. Attach the front wheel suspension to the front bottom end of the frame in the same manner, i.e. press the black button at the bottom of the axle and press the axle into the axel hole from underneath. Release the push button.
4. Check that the front wheel is securely fastened by lifting the frame from the surface and pulling the front wheel downwards.