How to install the language package?

Hi. I'm searching for three hours now, and I can't seem to be able to install the translation package for flexicontent. Please help. Thanks in advance.
I've downloaded the package, I've installed the translation manager, I've found out how to translate the com_flexicontent myself, but I want to install the allready translated package.

Maybe the package you downloaded isn't in installpackage and you have to upload it manually by ftp.

1) Open the package ion your pc, if there is an *.xml inside, the packe should be installable by the joomla-installer, -> 2). If there is no *.xml inside, you have to install manually -> 3).

2) Go to the backend of joomla -> extensions -> install/remove and install the package (the language you would install have to be installed for the joomla core befor!).

3) Put the files on the server by using ftp
Site: ~/languages/it-IT (<- your language)
Admin: ~/administrator/languages/it-IT (<- your language)