Trying to learn "Root"

Darn if the US Marine Corp use it in their training, then I have "got to" take a look at it. Now from what I thought was going to be a straightforward A4 booklet of rules to read say in 45-60 mins, I was a little taken aback with the wealth of rule related material. It was all beautifully produced, engaging and rich in "pleasant" detail - but I have to "get my head round it" so I can explain it to others. It is a competitive faction (players v players) game, most play is not collaborative (although there can be moments of alliance [that also could lead to betrayal]) so it is important to get the "rules right" (see below, three instruction manuals - a light introduction, example of play booklet [a run through of a few turns], then the "Lore of Root" which is the definitive guide which looks "medium to heavy"):

It is beautiful and I am keen to play.