To discuss the matter
My suggestion to begin with is the following
1 - Draw a map of your game: you can even do it by hand and scan it, this will use as a base for the editor (the map is a mandatory requirement for a new project in the editor). You can read good modding advice on the Mollwitz41 mod
2 - Define the scale of the game (turn duration, unit sizes, etc...) to help you determine your elements of the DB, such as units, leaders, structures, terrains...
3 - Make a list of the cards you want to have. A good mix is usually 1/3 red cards (events, one shot) and 2/3 black cards (tactics, other minor effects, can be redrawn). You may decide to have more events cards if you want to use them to "drive" your game, represent bad seasons, etc...
4 - Decide if you need to use the Tension Index feature (like in 6Days1967, Mali2012, Korea1950 or Berlin1945), i.e. something that move up/down on a scale and gives either VP or full victory and that can also be used to trigger some cards effects...e.g. if your index reach 10, you can decide that Spain will send more/less troops, etc...etc..
I would suggest that you put all the above and more in a single document and exchange it with us for further advancement.