Classic Style

Well, i am converting my passenger's side window reglator from a 74's manual roll-up, to what is marked as a 77 power regulator. The problem is, instead of the 2 parallel bars, this setup has a single bar coming off the regulator and then a pivoting bar off that. It also has a 3rd slide on a bar that looks like it bolts to the door somehow. I do not have the bolt hole provisions for this extra piece, and I do not quite understand how it works. If anyone has any ideas, or knows where I can get the info, please let me know!!

Thanks much,
Randall