The Vigilant I have has "tall" doors and a coal conversion kit. Early 1980's model. The glass door insert came as an option.
Here is how it was assembled. Assumong the cast iron inserts are removed first.
Lay door on it's face.
Insert safety screen into door frame. (3/6" x 3/6" grid painted black with 1/64" diameter wire)
Wrap glass with "U" shaped preformed gasket material. http://www.woodmanspartsplus.com
Insert wrapped glass into door.
Screw the cast iron frame to the door back to hold screen / glass / gasget in place.