waczny
I have no clue what you are talking about (for the mod you linked) but any support related to 3rd party mods does not belong on this forum. You need to contact the modder directly.
It works like a charm, but during the setup process it was asking for the Admin data, Helpdesk name, Database etc again.
You stated you setup a test environment so that would mean a completely new server/setup without the data from your production site. So of course it's going to ask for installation details.
Is there a way to just run it as a upgrade so it keeps the current information and just chances whatever I changed ?
You can do a full MySQL dump of the database and migrate it to your test environment. Once you do that copy over the include/ost-config.php file from your production instance to the test environment and update the needed information. Then you should be greeted with a clone of production.
CAUTION: If you clone your setup you will have two live instances running. It's ALWAYS best to disable the helpdesk and turn fetching offline before doing a dump of the database so that when you import the data to the test environment and connect it to the ost-config file it doesn't start running and pulling in tickets there instead of production. You basically want the test environment completely disabled so that it doesn't affect production at all.
Also If I make a backup of my mySQL and of the folder where I have my osTicket files (running it on Windows) before the changes I can always securely go back 1:1 without any risks? or is there anything else I need to backup?
As long as you take a full MySQL back (mysqldump command works best) and full backup of the site files, you should be good.
Cheers.