HI,

After downloading language files from languages addon, how do I install them and activated them in front and back end ??

Thanks for your answer.

Hi,

It's pretty simple. If you already installed another language on your joomla (joomla translations, not component language files), let's say German one, just go to FTP, navigate to: /language/de-DE/ and upload the german jomsocial language file to the german language folder. Format of the language file name should be as follows: de-DE.com_community.ini just like the original file is en-GB.com_community.ini.

To sum up.
1. Install Joomla translation (from backend: extensions > language manager) de-DE [example]
2. Login to FTP
3. Navigate to the /language/de-DE/
4. Upload your German language file there.
5. Done.

I hope that helps.