Lay extension ladder down flat on a work surface.
Slide the bracket over the top wrung of the non-operating half of the ladder. Position the bracket off to one side, approximately one-quarter of the way out from one edge of the rung. The bracket rests over the rung with the mounting holes below it.
Align the mounting hole in the pulley with the mounting holes in the bracket. Push the bolt through the holes in the bracket and pulley. Insert the washer over the end of the bolt and thread on the nut with your fingers.
Adjust one wrench to fit over the nut and the other to fit over the head of the bolt. Turn the nut clockwise to tighten it to the rung while holding the head of the bolt still with the other wrench.
Wrap the rope around a lower rung on the operating half of the extension ladder. The rope has a loop at one end. Thread the non-looped end through the looped end so that the rope is securely wrapped around the lower rung. Pull the non-looped end up the length of the ladder and thread it through the top opening in the pulley. Tie a knot in the non-looped end of the rope. Pull down on the knotted end of the rope to raise the ladder up. Extension ladders have catches that hold the ladder at various heights. Raise the ladder up slightly above the catch nearest the height you want and lower the ladder onto the catches. Let the rope hang down to the ground. Pull down on the rope to raise the ladder up, release the catches and use the rope to lower the ladder. The rope does not get tied off, it simply facilitates the raising and lowering of the ladder until it reaches the ladder catches at the given height intervals.