1- Download ZIP - Save to your computer
2- Open SuiteCRM and enter "Admin"
3- Go to "Module loader"
4- Upload file from step1
5- Install it (sorry: hit the button install)
6- Go to "Admin" enter "Repair" and apply "Quick repair and rebuild" for languages
7- Log out SuiteCRM
8- Log in / pick your language
Enjoy!

Easy enough? You don't need FTP, permissions, script, nothing. Use your browser and SuiteCRM instance
Or take the visual guide: Install a new language - TranslatingSuiteCRM -sites.google.com/site/translatingsuitecr...nstall-new-languages

To download:crowdin.com/project/suitecrmtranslations
( first pick your language then download zip)