I really appreciate you going to all this trouble for me, Joe. Thank you.
Nothing pops out. Matter of fact, I can't even figure out how to get the screen out, lol. These are not high end windows, but they're better than the aluminum frame single pane windows they're replacing.
What about this thin channel just inside from the edge that runs all the way around the window? Are there clips that maybe go into this channel and those clips get screwed to the frame? There appear to be grooves or teeth inside that something could lock into. I saw clips mentioned in directions I was reading for Pella, but I couldn't find any other mention anywhere. A search looking for the parts didn't produce results either.
If this channel isn't anything, I believe that leaves me with two options. Build a frame around the window putting screws in through the wood into the vinyl. This would allow me to use the frame I build to secure the window to the house and level the window. My biggest concern is will the vinyl actually grip the screws and hold torque?
Or, do like you mentioned Joe and go through at the two points you identified.