Number 1 is the part that I mentioned that connects to the glass and it has a roller down farther that you can't see in the track itself.
One of those parts is made to pivot to allow the rollers to not bind up with the track, and the other one on the glass is not supposed to move. (this one keeps the glass from moving for and aft.)
2 is the stop that limits the travel of the glass so it doesn't go up to high.
3 are the in and out adjustments that determine where your glass ends up contacting the seal at the top of the window opening. (test by moving that adjustment with the window all the way up.)
That same adjustment determines how much pressure your glass puts on the quarter window vertical seal.
Wait till you start leveling the glass in the opening front to rear.
That's a fun one, and I can explain it to you in detail when the time comes.
Some people would be shocked to see what mods I have made to some of these parts
In my drivers door all the rollers are solid nylon about 3/8 thick and the pins they ride on have all been replaced with fine thread 1/4 inch bolts and nylon lock nuts.
It not only replaced some broken rollers with something a lot tougher, but gave me 4 more points of glass adjustability.
Of course it took me all of one day to do one door, but man what a difference.