There should be a hole on each outside edge of the door about 1/4" in
diameter.

Insert a Philips screwdriver in the hole, by turning the screw that is
attached to the roller this will allow you to raise and lower the
rollers and remove the door correctly.

I can't remember if it's clockwise or counterclockwise to lower, but you
will see the roller go up into the door depending on which way you turn
it.

Once you get the door off you can look at the bottom and see how it
works.