In order to install SMF in a language other than the default English, simply select a new language from the drop down menu on the Installation screen in Softaculous.

If you are looking to install additional language packs to an already existing installation, you will first need to download those packs. You can easily do so from the following link:

http://download.simplemachines.org/?smflanguages

 

Once the package has been downloaded, upload it to the root directory of your SMF and decompress it there.

You can also instal new language packs from your SMF admin panel->Admin->Configuration->Languages->Add Language

You can switch between installed language packs available on your forum from your SMF admin panel->Admin->Configuration->Languages->Edit Languages