If memory serves me right.... Have the spring end connected to the pulley leaving the rest of the spring hanging outside and in the slot in the housing. Secure the pulley to the housing.
Now, crank/turn the pulley with your hand so as to pull the spring into place.
Continue cranking the pulley until it's completely wound.
Holding the pulley from unwinding... Insert the cord into the retaining hole and out the hole in the housing.
HINT: Some of us have the cord already wound on the pulley with the handle end sort of folded over so it stays put until the final stage whereas we could flip the end out with a scribe, screwdriver, something.
Use caution so as not to lose your grip in the pulley or the cord... you do not want that pulley to freely unwind until you're ready!