[Fritz Peyerl]

It is confusing when you see the spring laying there, but the left side end goes onto the shaft and than you start winding up the spring till you come to the inner end and that end hooks onto the plastic housing.
Best thing is to pull out the seat belt as far as you can and than lock it into place. That way you can wind up the spring and with out retracting the belt and also when the spring is wound tight, you know it will not jamm up.

good luck