If you are a first contributor, the first important step is to contact previous translators to coordinate the work with them.

Get the po file for your language from the repository: PO

Get the latest generic PO template file: POT

Put both files on the same directory and open the po fifle:

$ poedit <lang>.po

And update it using the POT file, go to menu Translation -> Update from POT File... and select darktable.pot file.

And start translating. Saving will update lang.po.

1. Save your translations in the Poedit application (File -> Save in the menu).
2. Locate the <lang>.mo file next to the <lang>.po file.
3. Rename the file to darktable.mo and move it to the appropriate folder in the darktable application bundle.
4. On macOS, the folder would be /Applications/darktable.app/Contents/Resources/share/locale/<lang>/LC_MESSAGES.
5. Launch darktable and select your translation under Settings -> General -> Interface Language.

To avoid lot of noises when having diff from a po file one can filter out the output by using the following filter:

$ git config diff.po.textconv "msgcat --no-location --no-wrap --sort-output"