It's a simple latch; I had a picture of it but lost the hard drive temporarily. I made a simple tab for my plane that just rotates on a screw mounted in the spar, it holds the window open even in flight, if I want. You may also want to consider a latch to hold the window closed. Mine flapped in the propwash, so I made a couple of tabs for the door mechanism that latch the window closed as well as the door. You can still unlatch the window to open it without unlatching the door.

1st pic is the tab to hold the window open, the others hold it closed: