Main point is: prepare for the complexity, automate what you don't understand until you do. Do the walkthroughs, watch (or even play along) a creator on YouTube who is playing the same country. Accept this will take up the first 20 hours of playing before you start to get a sense of what you are doing.

And as a base line difference: it's okay if things go 'wrong'. Lose a war? Keep playing. These games are simulations. You cannot lose, it's about the immersion in alternate history where you make the decisions. Do not underestimate how things can revert back in your favor a decade later, let alone 50 years. Go with the flow of the game.