Your first mod

Welcome to the flight line. A Ground of Aces mod is a folder of ordinary files inside the game's Mods folder: JSON, CSV and Python files for missions, quests, scripts and game data, and models (.fbx, .glb) and PNG images for new art. You do not need a download, an account or programming tools. Missions, quests, scripts and data changes need only a text editor. New art needs the program you make models or images with.

Your first mod in five minutes - just the game

You will make the wooden wall cost one plank instead of two.

1. Open the Mods folder. Start Ground of Aces and in the main menu click Mods → Open folder. A file window opens. (If you would rather find it yourself: on Windows it is %USERPROFILE%\AppData\LocalLow\Blindflug Studios\Ground Of Aces\Mods\, on Mac ~/Library/Application Support/Blindflug Studios/Ground Of Aces/Mods/.)
2. Make the mod folder. Inside Mods, create a folder called my_first_mod.

3. Give the mod a name. Inside my_first_mod, create a text file called config.json and paste this into it:

   {
     "Id": "my_first_mod",
     "Name": "My First Mod",
     "Author": "Your name",
     "Version": "1.0.0"
   }
   

   Name is what the Mods window shows. Id is how the game tells mods apart: lower-case letters, digits and _ only. All the fields are explained on How mods work.

   Use a plain text editor: Notepad on Windows, or TextEdit on Mac switched to plain text (Format → Make Plain Text). Check that the file really ends in .json and not in .json.txt.

4. Make the change. Inside my_first_mod, create a folder called CSV. The name CSV must be exactly that, in capital letters: the game recognises content by its folder names. Inside CSV, create a text file called ResourceCost.json and paste this into it:

   {
     "Commands": [
       { "Command": "Replace", "Id": "wall_wood", "Cells": { "Planks": 1 } }
     ]
   }
   

5. Load it. In the game, open Mods and press Refresh. My First Mod appears in the list, switched on. Load your save.

6. Look. Open the build menu: the wooden wall now costs one plank.

That is a complete mod. You now have this:

Mods/
  my_first_mod/
    config.json
    CSV/
      ResourceCost.json

From now on it always works the same way: change a file, go to Options → Quit to main menu, load your save again, and see the result. Testing and reloading explains the details, and How mods work lists every folder a mod can have.

Back up your saves

Modding is a developer preview. Copy your save files somewhere safe before you try a mod.

Pick your way from here

Your goal	Where to go
Build a mission in the game, without writing files by hand	The Mission Editor in the game's main menu. You fill in fields, and it checks your mission when you save it. See Without an AI agent.
Write mods by hand	A text editor and these pages are enough. Read a topic page: Missions, Quests, Scripting, CSV tables, Maps, Objects, Airplane skins. They show every file and field, with examples you can type in. Write your first mission is a good next step.
Copy working examples and check your mod for mistakes	Get the modkit, then follow Without an AI agent.
Let an AI agent build the mod for you	Claude Code, Codex or the open-source OpenCode. Start with Get started with AI modding.

Keep the Glossary open in a second tab if a word is new to you.