It sounds like you are describing a Jealousy window?? If so, there should be two screws on the bottom side of the trim that holds the glass in. Back the screws out and save them for re assembly. A lot of these had a vynil or rubber gasket that encircled the window. If its not torn or damaged, pry out the little bits of glass and save it to rewrap the new glass. Have a glass shop cut you a new pane, remembering to allow for the ggasket. Install in reverse. A little wd40 will let the gasket and pane slip in a little easier. Be sure to get tempered glass, not just single pane strength. Glass cutting is a talent ive never had much luck with, so when i replaced several in my camper years ago, i went with acrylic, which is stronger than glass andd ckearer than plexiglass.Both can be cut with a utility knife ( score both sides and snap) or with a jigsaw set to low speed with a fine toothed blade. It can be bought in various sized sheets at home depot or lowes. In fact, i have a broken pane in the lower section of the jealousy window on the front of the shasta, so you have reminded me that SOMEDAY ill have to get out there and fix it--- thanks :0( lol,
Be careful and good luck.
edit - the bus has "hehr" windows fwiw
