This project is set up so anyone can contribute by suggesting translations and voting on existing suggestions.
The language coordinators will then proofread the suggestions and approve/reject them.
The generated language packs will only contain approved translations to ensure a high quality of the translations.
The language packs generated by Crowdin can be downloaded in the translation overview (or using the URL https://crowdin.com/download/project/joomla-cms.zip) and should be able to be installed in the Joomla! Extension Manager.