I started installation but: “Failed to download and install the required files. To install a language manually, upload the language folder to /web/htdocs/www.tiche.info/home/gibbon/i18n/ on your server and then refresh this page. After refreshing, the language should appear in the list below.”
So where could I get the language folder?
I’ve read this Steps:
"Make sure your Gibbon installation has a 100% passed system check (you will need to installed certain PHP extensions).
Done!
Install the Languages you want.
How?
Create a System Variable in Windows called LANG
How?
Change the variable to the language code you prefer (requires adding the language to the Gibbon installation). For example: LANG=es_MX to use Gibbon in Spanish
How?
Restart Apache server
How?
Refresh browser
This I can manage 
Start using Gibbon in the language you prefer. (Note: Windows must be set to the language that will be used in Gibbon).
Done, I managed to fill the Italian translation folder.
But at the Step 2:
Database “Sql706744_4” not found and unable to create one. Please manually create the database, or provide account that can create it.
Error details: SQLSTATE[42000]: Syntax error or access violation: 1227 Access denied; you need (at least one of) the SHOW DATABASES privilege(s) for this operation
I am quite sure the db credentials are correct
But now I cannot go any further.
Thanks,
Close this since I installed Gibbon using softaculous
Great to hear you found a solution, and even though you’ve switched approaches, thanks for sharing your steps along the way just in case it helps out the person with a similar question.