Obvious answer is "an excel sheet" or "don't" but tbh I play alot and it makes me feel like a weirdo The best I got is that it kinda reminds me of a more strategic sim city, but with a world map. You have a bunch of little people like sims and you control their lives by deciding things like taxes, what the country builds, and what the laws are. Oh, and you can be an imperialist colonizer and invade other peoples countries
Imagine Vicky 3 but gooder
spoiler
It's the same map-brain grand strategy principles as Crusader Kings, Hearts of Iron, or Victoria; but with different game mechanics tied to the specifics of the time period. TBH I haven't really spared it a thought since Stellaris, Crusader Kings 3, & Victoria III came out but I had a ton of fun with it years ago.