I received my darning foot today from the White Sewing Co. The back says something about a spring, but the contents inside do not have a spring. There is only a closed toe foot and a pin that looks like a screw.
Do you think they forgot the rest of the parts??? Is this what it should look like? Because the universal low shank darning foot I saw at the quilt shop looks different. ANSWER
I would suggest taking your darning foot to your nearest sewing or quilting store. They can show you how to attach it to your machine. You could also call the White Sewing Company, and ask them about the spring. After all, it's their product.