The gasket on a window is a very thin, flat ribbon gasket. The gasket that Leisure Line ships with their door glass has a self adhesive on one side. You pull the paper tape off the adhesive and stick the thin gasket over the edge of the glass wrapping it over the edge onto the sides of the glass. This makes a perfect 'U' shaped gasket around the perimeter of the glass.
Remember, don't try to clamp the glass solidly to the door, the glass will break. The door and the glass expand different amounts and need to have some 'give' between them. That is why the screws that hold the glass in place have soft flexible 'washers' under them that actually apply the slight pressure on the glass.