Umm... what kind of thing did you have in mind? For beginners? For techies?
If it's beginners there are useful videos like these:
https://tilvids.com/w/f747058d-3991-4046-a1c9-29c184daa0ff
https://fedi.video/w/m9L9gYXJypnywSyChQLxnd
https://framatube.org/videos/watch/4294a720-f263-4ea4-9392-cf9cea4d5277
If you're a hardcore techie, there are many conference videos about ActivityPub, the protocol which powers most of the Fediverse: