I’ve recently added a few articles to the in-game FAQs section for Atlas. Hopefully, some of these may help clear up some confusion, or at least provide a baseline amount of knowledge to some of the mechanics. I’ll keep working on adding more, but please feel free to request specific topics.
[?] Atlas Castles and Infrastructure
[?] Atlas PvP Combat Overview
[?] Atlas Combat Flowchart
[?] Glory Mechanics
[?] Primarchs Overview
[?] Troops Overview
[?] Targeting and Bookmarking Locations
Relevant mention to Gox’s Atlas Guide for more in-depth looks into strategy and more.