So... I was procrastinating in youtube and I stumbled upon these Warhammer video series by CA's own Joey Berry.
She has a playlist dedicated to the Lores of Magic (the different magic schools) which may come in handy for some people:
First episode:
The whole lores playlist: https://www.youtube.com/watch?v=nhMS...9EB72E0B3A00E6
There are some 40ish more videos with the tag "Warhammer Joey" that seem to touch a little bit of everything in a more general way, as a newbie introduction to Warhammer and wargaming . Check out the first one (Warhammer Joey #1):
(sorry Joey if all this was meant to forever remain hidden and forgotten in the depths of a dark cave guarded by mountain trolls).