Total War: Warhammer

I've always wanted to really get the Total War games, and despite multiple run-ups at Shogun 2 and Rome 2, and previously Warhammer III, I haven't been able to really get a good grasp on things. I have gotten fairly deep into campaigns and eventually reached a point where I felt stuck, or perhaps lost.

I'm a fan of Warhammer, mostly on the 40K side, but more and more on the fantasy side as well. As of this writing, Games Workshop has revived the old fantasy setting in the new game Warhammer: The Old World, which is itself a re-invention of the "rank and flank" style game that Warhammer Fantasy Battles was prior to it being retired and the setting being reinvented as Age of Sigmar.

I've been caught up in the hype around The Old World coming out, but rather than drop $300 or more to buy more plastic models that will sit around for months or years before being painted, and then only rarely played with, I am working through it by taking another charge at Total War: Warhammer. 

At one point or another I bought the first of the three games on Steam, and so I figured I would play it some before eventually moving on to the second and eventually settling into a groove playing the third, which I have already had some experience with. I like to get the full context of things, though, so this is my planned way of going about that.

I have an army of Ironjawz Orruks (orcs) for playing Age of Sigmar on tabletop, some of which are the same models used in The Old World for Black Orcs. These were that, originally, and then brought forward into AoS as 'ardboyz. Recently, though, 'ardboyz got a new kit, that look different and are armed differently. I bought my models when I did, though, and so I'm left with the old 'ardboyz models which are also the old Black Orcs which are also once again the new Black Orcs, for the new game I don't play yet. But that I might at some point. At any rate, I am playing Orcs and Goblins in Total War: Warhammer, at least in my first campaign.

I've been enjoying the RTS battles so far, but the best method to manage grand strategy map eludes me. Should I just sit and wait and build up a massive army and go seize the neighboring territories? Or is it better to have multiple smaller forces? How do I keep my populace from being too restive at home, and which settlement upgrades should I pick, and when? Why do my armies have 5-6 different stances they can take on the map? Which of those is best, for what, and when? These are the questions I'm grappling with at the moment. Nevermind actual grand strategy, I just need to get my bearings.