9
Ensure that the twistlocks of the shafts are loosened by rotating them counter- clockwise.
Compress the spring loaded pin in the lower shaft and slide it into the middle shaft until the pin reaches the adjustment holes. The pin will spring out and click into place.
Attach the middle shaft to the upper shaft in the same way.
Once shafts are assembled, lock them in position by rotating twistlocks clockwise.
The upper shaft assembly location uses two spring loaded pins to strengthen the joint, one on either side of the shaft