Installation Help. New to WP.

I am new to this and I am lost. I tried to fill in the database info but I don’t think it is right. How do I fill this in.
define(‘DB_NAME’, ‘wordpress’); // The name of the database
define(‘DB_USER’, ‘username’); // Your MySQL username
define(‘DB_PASSWORD’, ‘password’); // …and password
define(‘DB_HOST’, ‘localhost’); // 99% chance you won’t need to change this value

When I did it how I thought I got this error.
Error establishing a database connection! This probably means that the connection information in youn wp-config.php file is incorrect. Double check it and try again.
Are you sure you have the correct user/password?
Are you sure that you have typed the correct hostname?
Are you sure that the database server is running?

Can you help?