This page allows you to import a translation provided in the gettext Portable Object (.po) format. The easiest way to get your site translated is to obtain an existing Drupal translation and to import it. You can find existing translations on the Drupal translation page. Note that importing a translation file might take a while.

Import translation
A gettext Portable Object (.po) file.
Choose the language you want to add strings into. If you choose a language which is not yet set up, then it will be added.