Jason Morningstar was too humble to mention his own tutorial setup for Night Witches, which serves as both a rules primer and setting primer.

I agree though that it is really challenging to ever really understand a game until you see it at the table, in large part because of the complexity of the rules, and in large part because people learn at different rates and invest at different rates, and the balance of knowledge and investment at the table is such a big part of what makes RPGs and complex boardgames work at all.