I agree, there are so many different types of shower setups, that is making it really hard to do a "google search" for it.
Here is a photo of the type of shower I have.
It looks like it all hangs from the bar at the top, which has tracks and stuff inside. The screws that are loose are inside that bar, holding the hardware to the glass panes. They are coming loose and jamming, so I cannot open the doors.
This weekend, I will pull that top part off and see if it all comes sliding out one end or the other, tighten the screws, re-align everything, and hope it all goes back together. I just hope that is how these things come apart, and I can get it all back together again.
Be a good opportunity to clean calcium and soap-scum buildup off the glass. Lay it all on its side and scrub HARD.