Since you have officiated other sports, you have already won half the battle...knowing how to be an official. Now you would just have to learn the sport.
From a purely physical perspective, no
VB is not hard compared to football and basketball.
From a mental perspective, it is every bit as taxing, if not more so.
The "basics" are just like any other sports - know and apply the rules, learn and use the proper signals. After that, it's about working games and getting better as a
VB official.
I will say that it helps if you have played or coached the game at a competitve level, but I think that may be true for officiating any sport.
I believe you live here in the West Phoenix area, as do I. If you want to talk about this a little further, shoot me a private message. I will be happy to discuss things with you.