Unless you have the new type torsion springs that are preloaded with a worm gear drive attached to the torsion shaft, you have to wind the spring manually using two rods approximately 18 inches long. You place the rods one at a time in the spring retainer and turn it approximately 90 degrees at a time until you have the specified # of turns of preload applied. (usually 7 to 9 turns)
This process becomes a repetative action since you will have to turn, remove the other rod, insert it into the next hole, turn, etc, etc, for 30 or 40 times. One lapse in mental concentration, one slip of the hand off of the rod, a rod slipping out of the hole because it isn't fully inserted, etc can result in one of the rods flying around and ripping part of your jaw off, or knocking you off of the ladder, or punching a hole in your head.
Pay attention, concentrate, don't make mistakes, and most importantly, don't take the job lightly!
Good Luck, Be Careful!