1. Did you put that files into language folder? Translation works for other lanugages so it should be no different for your language.
2. Using shortcodes as desribed in the documentation http://www.dfactory.co/docs/download-attachments-plugin/
After you register and login to the site, you may post all plugin support questions in the Support Forum.
If you need to provide private info, please create a ticket and then reply to it using Set as private reply option.