Good to see you up here myclockrepair,
You should be able to unscrew the 4 knobs on top of your clock and lift off the top. You can then slide the glass up out of the grooves in the 4 case pillers. If the pillers are loose at the bottom the glass and door may fall out so take care to secure things before removing the knobs (nuts).
Hope this helps myclockrepair,