I am having trouble installing a window regulator

1991 300E mercedes, 4 dr sedan. I'm trying to replace the left front window regulator. I got it in, but it doesn't raise the window correctly. One side is higher than the other. There is a loose part, about six inches long that I don't know where it goes. When I took the old one out, I failed to note exactly where this part was. It's like it almost fell out. Do you have a diagram to show me where to put it? I feel so ignorant. Help videos seem to take it for granted that anyone can reattach the window to the regulator. I've repaired cameras, rebuilt an engine or two, even rebuilt a gm hydromatic transmission, but can't figure this one out. Help please!