The chair needs to be at the top of the track. Remove the two "Stop Slides from inside the top of the track. Run the unit to the top stopping it before the end of the track. Remove the seat ( un screw cover plate, disconnect the wired connections and unbolt the seat stem. Lift off seat) Then, using the hand winder "wind" the motor unit off the track.You might find it easier if you remove the plastic "Knob" of the hand winder, fit a second nut to the shaft,lock the two together then use a ratchett from a socket set with a 17 mm socket and use that to wind it.
M.Westlake, January 2016