Installing language after installing Drupal 7

  1. Download the language file from here.
  2. You will find a directory named translations inside the directory of your profile. for ex. standard profile: profiles/standard/translations.
  3. Move the downloaded .po file inside translations folder.
  4. Go to Modules and enable Locale module.
  5. Go to Configuration and choose Languages.
  6. Click on add languages, choose your language and save configuration.
  7. Make it default and save configuration.