Yes, the connection name can be whatever you want.
in your sites control panel, you should be able to access the database you created using PHPMyAdmin, in PHP MyAdmin, the MySQL Server address will show in the top left corner
When you create the database, you would have set a username, use that username
when you create the database, you would have set a password to connect to the database, that is the password to enter
This indicates a problem in the site settings, specifically the URL Prefix in the Testing server connection settings.
make sure the URL Prefix for the testing server is correct.