I'm wondering if anyone has a suggested resource for absolute beginners. I imagine over time Urtuk will get its own Wiki with guides posted there but I think most people are likely to stick around with some kind of gentle introduction to the game's more complicated mechanics.

Hello,

on steam page, there is a short introductionary video explaining very basics of combat and campaign.

Also we have already wiki: https://urtuk.gamepedia.com/Urtuk:_The_Desolation_Wiki

Hope it helps!