This is fixed with adhesive and requires special tools to do properly.
You will have to remove the rear door panel to gain access to the inside of the door. In the door there is a brace directly under the molding that separates the Fixed glass from the window. If you undo that brace the old fixed part will come out and ou can slide the new window in. It took me less than an hour to replace mine.
A window that is broken, or needs to be fixed
This is called a "transom". In the U.S., this name applies if the window is fixed or if it opens.
I think you need to replace the spirals, normally a black tube about 15mm in dia which is fixed to both the frame and window and holds the window open at any height
The rear window has no control. It is a fixed window.
You have to take the window shutters off their mounts in order to replace them.
HOW DO I REPLACE WINDOW REGULATOR MOTOR ON PASSENGER SIDE WINDOW
To replace the Ford Explorer rear window hinge, you have to buy a similar window hinge. Use a screwdriver to open the hinge and replace the hinge but fitting it in the window.
video on how to replace window lift motor on j30
YOur motor is going bad, have it checked. you might need to replace it.
which window ? door or windshield or back window ?