It took me a long time to get into it, and i wish i had found a guide like this while starting off, but i could not. I decided to make this guide because this game has no such thing as a tutorial (you can't really count that flight tutorial that tells you to do stuff but not how to do it as a legit tutorial.) Then at that point you can either continue playing as a humble merchant or bankrupt assassin with all your well earned new knowledge of the game, or you can start an entirely new game as something else, but not before reading my section on 'Selecting Your Start'. > Combat pt.1 -> Combat pt.2 -> Bankrupt Assassin Guide.
Then save your game, start a new game as a Bankrupt Assassin and read Intro -> Configuration and Optimization -> Start new game as a Humble Merchant -> The Start -> Upgrades. Although its completely up to you how to use this guide and it's viable to just read it from start to finish all in one go, i recommend you do things in the following order in the name of playing the game as much as possible whilst reading the guide.