OK....if u are gonna install something like PHPBB, Wordpress, PHP-Nuke and want to give the MYSQL DB information...then go as follows....
1. Create a new Database using PhpMyAdmin
2. Note the name of the Database, Your_Database_Username, Your_Databse_Password
3. Open the install.php file, in Database Name fill your databse name, in the username and password fields fill ur username and password and click install....the php will automatically connect to the mysql server's default port.....and will install the application....
U can make new databses, assign usernames and passwords through your servers MySql database manager....Generally if u have Cpanel installed...U can acces it through.....*www.your_site_name.com:2082/frontend/x/sql/index.html