How do I thread a sliding door built into the wall?

Try this:https://www.hometips.com/repair-fix/pocket-door-repairs.html

The ends have a spring with a small plastic circle on the end on the floor you need to rest the bottom screw in the bracket on the bottom of the wall it’s a small circle just pit the nut on the end of the door in it it just rests on it then line top two screws up the one on the top of the door the one at the end of the door will go down with a spring pull down and hold it line up with the top rail and let go and your in

If you remove the trim around the door and where it meets the wall, it should slide out far enough to take the door off completely/ access the top for repairs

I just lifted mine up a bit and put it back on the track took all of 10 minutes.