Here's a photo mounted. The tab goes in front of the hanger.

If the pivot bolt is stripped on the stop washer (which is typical - the stop washer and pivot bolt are supposed to lock together) take a allen wrench to the front side when tightening the anchor bolt and rotate the pivot bolt to apply tension on the spring, then tighten the anchor bolt - the derailleur should rotate rearward and have tension when pushed forward.

You may want to install one of the lower 2 first to see how the spring tension works when installed. It may be a bit tricky the first time, but once you understand how it works, it is easy to get right.

Good luck

Joe