1. Before connecting the upper and lower tubes, slide the adjustable handle onto the upper tube at the middle section
2. Slide the upper tube inside the lower tube and align the screw holes
3. Insert the joint-fixing bolt through the aligned holes in the upper and lower tubes and secure the other end with the joint-fixing knob
4. Move and rotate the adjustable handle to a comfortable working position
5. Tighten the handle knob

NOTE: Do not try to install the adjustable handle after the tubes are assembled.

NOTE: You may have to carefully move the wiring inside the tube to one side if it blocks the path of the bolt. (Use the shipping wire to maneuver the electrical wiring; do not use a sharp tool.)