I dont know a better way of a tutorial for this game than what is ingame. Otherwise I would already have made a guide for SDN44.
But covering the units or tactics is not useful at this point, when the people dont even fully get even a few divisions to work, before they surrender.
They need a certain own wish to be good at this game, but then the rest works. And this is a game that introducts over time. Its designed to be played over a larger time period, not play it 2 hours and then unfund it again, or playing it 50 hours and then its played through. Instead, you play it over years, but not every day 4-8 hours, I think that does not work over a longer time (more than some months).
I think the people are not happy about playing it a few hours and then having to admit, that they did not, unlike they expected, have it learned fully, seen everything, and can judge what they have here. I think that is a good sentence. Strategy comes from the long hand, unlike an ego shooter. I see the strategy genre developes in a longer, slower period, but also stronger.
I can even see my 20 years old games develope today. I play them still. I never had thought.
They are not worse than newer games. I never had thought. They stand on eye-to-eye to modern strategy games.
But its difficult to show somebody how he shall play this game, because he shall not follow your instructions too strictly, but invent his own. From themselves, they dont understand that they are the smith and the game is the anvil, not they being part of a already prepared game (they just need to follow). Leadership is a very big power.
Unlike in other games, balance is not that vital, no matter how it is, because you can adapt your people a lot with just standard commanding work to completely trick out any balance system, if the relations are not 1:1000 or so.
1:2 or 1:3 you can easily compensate. (Every game is different).