You need to start at the barebones basics. You can’t have an economy until you have all the systems that make up that economy.
Long before you even touch the economy, you need to flesh out the simplest interactions that make up your game world. The map, the units, basic objectives, user interface, etc.
My map generator started with “place 2 hexagons next to each other” and grew from there.
Figure out what your game “board” is, how it represents your world, how you interact with it, etc. Then move up to having units and other features exist on that board. Go bit by bit and work out each problem as you go. Eventually you will have a game, given you are persistent enough.