When Game Kitchen installs, it creates a template directory in your app data directory. For me, this directory is C:\Users\Kevin\AppData\Roaming\GameKitchen\template. In this directory is a collection of lua files which get copied to the project directory whenever a new project is created. By default, it contains main.lua, globals.lua, conf.lua, and math/vector.lua. Feel free to change it to your liking.