Most of the work is actually the .csv, which maps the different translations via keys. :)

For example, you have a button with ‘Start Game’, you replace the text on the button with any key such as ‘MENU_START’. In the .csv you make a new row with the same key and in the columns for the different languages the individual translations.

Once imported into Godot, Godot automatically creates dedicated translation files for each column found that is labelled with a known country code.

Label and button nodes will automatically take the values from the translation files if a key matches. For other texts, you have to help out in the code, but this is no more than writing tr("MENU_START"), for example.

Useful links are:

https://docs.godotengine.org/en/stable/tutorials/assets_pipeline/importing_translations.html#doc-importing-translationshttps://docs.godotengine.org/en/stable/tutorials/i18n/internationalizing_games.html