You'll often be asked to supply your MySQL database information in order to complete a software installation.
First, make sure you've actually created a MySQL database along with an authorized user (see the other article about this). Make sure to note:
the database's name,
the username of the user authorized on this database,
the user's password.
You should now have all the information needed for your web software:
Your hostname should be: localhost
Database name: the name of your database created earlier (generally takes the form cpaneluser_dbname, where cpanelusername is your WHC username)
Username: the name of the MySQLuser authorized to use your database (NOT your cPanel username).
Password: the password for the MySQL user authorized to use your database (NOT your cPanel password)
If a port is asked, simply leave the default port (3306)