The great folks who run Milcopex have an interesting schedule of Zoom-based seminars coming up. The following web page contains information on each seminar, how to connect with Zoom, and information about Milcopex itself. Several of the seminars are on military-related themes.
https://milcopex.org/advance-speakers
Note that recordings of past Zoom presentations are available on their website as well.
We found out about the rich Milcopex offerings from The HUB at the APS website. If you are at all interested in using a good example of social media for philately, it is worth a visit, and worth signing up. See: