A country must not share a tag with any other country. This is how a country is referred to in all of the game's script.
Add a large, medium and small flag for each ideology to the /gfx/flags folder.Add the country's name to any /localisation/english/*_l_english.yml file that uses the UTF-8-BOM encoding.Buildings will not be assigned to the country properly otherwise. Create an OOB file in /history/units and load it within the previous country history file.txt file in the /history/countries folder, with the first three letters of the filename being the country's tag, and fill it with the starting historical information. Define the country leader and optionally advisors and unit leaders in /common/characters.Create a file in the /common/countries folder with the same name as the one that's linked in the country tag definition.
Define a unique 3-character country tag in any /common/country_tags/*.txt file.
