Now I'm tired of searching or trying to understand, sorry. Ten hours to configurate the all package are to much for my patience. Wamp didn't take me so long.
The last problem is indicated in the title. I've set new passwords as recommanded by the xampp security, among others the one for phpmyadmin, user "pma".
I've also modified permissions on httpd.conf, which modifies permissions on Gedit, if I understand well, but I probably don't. This was to allow scripture in htdocs. With no thanks to xampp support, I found the steps on a personal website.
Anyway, when I now open Phpmyadmin, I have no rights (?), that is, it seems, only the ones of pma user, user I'm told to use.
Reminding me of what I did for wamp configuration, I tried to modify password in config.inc.php, the password for "root" though. But if i'm identified as pma, I suppose it's pointless. Anyway (again), when I try to modify the file with gedit, I can't save it. Because Gedit can't create a back-up file.
I then found some linux instructions on phpmyadmin site to copy config.inc.
(cp config.inc.php config/ # copy current configuration for editing
chmod o+w config/config.inc.php # give it world writable permissions).
But I still can't register modifications on gedit.
I don't what is the problem, nor where it is precisely. And honestly I don't really want to know at this point. Just tell me what else is to be done to use this tool without having to build the tool first. I can try to understand some new things, maybe I'm too lazy to understand others, anyone has its priorities. But, "easy to configurate", really?
Consequently, thank for the help.