First read this about the recommended procedure concerning translations. Import translations is a part of this procedure.
Find an explanation and solution for the errors that might occur during an import here.
With this option it's possible to import a translated file with the translations of one kind of field (label type) and per language.
Two import formats are possible:
unique translations. For an example file and explanation of the columns click here.
non unique translations. For an example file and explanation of the columns click here.
For an extensive explanation of the different formats and possibilities also see Export translations.
Translations can be found under the Management tab -> 'Import translations'
Overwrite existing translations
If unchecked, only empty translations are being overwritten by the import.
If checked (default) the filled translations also be overwritten. This can be desirable if incorrect translations have to be corrected in one go.
Take notice with importing a unique import: one word can have multiple translations in another language. This can be a deliberate choise. With a unique import with this option checked, this is completely being overwritten. Therefor, always check in advance through Export translations which translations aren't unique (column UniqueTranslation).
After clicking on 'Select and import file', a screen opens in which the import file can be chosen. As soon as "open" is clicked, the progress is being displayed.