It's a complicated game, and figuring out everything thats going on is part of the fun.

I would start with a goal. Lets say abolishing slavery. Laws are different for each country. Hawaii and Great Brittain don't have slavery but most countries do start with slavery. In order to pass laws you need to have interest groups that support it, showed here. The landowners are the ones that will want to keep slavery the most. So you can see them as your primary antagonist. The interest groups most against it are the intelligencia and the trade unions.

Now that you know who your political allies and enemies are you start to think about how you can make them less powerful. The more industrialized a nation is the less powerful landowners are going to be, so focusing on building up industry will reduce their power over time. At the start of the game you will be able to suppress or bolster different interest groups, so using your authority for that early is a great idea. You can also try and pass a law that you know will lead to civil war, say abolishing slavery at the start, then you can see which provinces are going to stay loyal or not. Backing off and then militarizing those loyal provinces so you can feel confident in winning a future civil war is a great idea.

Basically the game is about setting goals like, expanding gdp, passing certain laws, raising standard of living, conquering/colonizing territory, and then deciphering the game's systems in order to make that happen. I almost lost this campaign because I decided to centralize my bureaucracy in a single province that ended up not staying loyal during a civil war. Because of this we didn't have the infrastructure to collect taxes during the civil war and I was actually in default before I managed to barely clutch out the war.

If you enjoy the idea of playing a game that allows you to establish socialism, and the depth of the systems at work seems interesting to you, I'd give it a try. It's a neat game. Two countries I'd recommend to start are Japan and Iran. Both start with a lot of different resources so you don't have to conqueror to industrialize effectively. They also both start isolationist so you don't have to worry about the big powers free trading all your important resources away, it was a huge problem when I played sweeden. It was basically this garfield comic but replacing garfield with france.

You construct buildings and that impacts your society and economy in different ways. You also pass laws which move your society into different directions. If you are completely lost there are letsplays and tutorials on youtube. If you need help really badly we could also play a coop game and I could give you some pointers. (Im pretty flexible timewise due to work from home). I took me about 20h to get the general gist of it.

You dont "really" have a goal but its fun to increase the living standard of your country and try 2 industrialize and have your peoples literacy rate increase. (Aim for a high GDP etc)

I'd start with a country that doesn't have that much going on and can mostly just do it's own thing like a nation in south america or countries like portugal or belgium, these are fairly peaceful and small nations that can do their own thing by industrializing and doing some social reforms. IMO you'd best stay away from building communism at the start because countries get really pissed at you now and I'd stay away from countries that start with a huge amount of problems or things to do at the start, so Qing, Prussia, Japan, East India Company, any italian country. Just figure out internal politics and internal economics and you'll learn quickly.

You just pull levers for about 10 hours until you kind of understand what's going on. And then you watch YouTube guides for how to marginalize the landlords