The host should be left as
localhost
In regards to the creation of the database, username and password, please read below:
1 - Login to cPanel
2 - Navigate to the MySQL Database section in cPanel
3 - Type in the name of the database in the textbox that correspends to "Db:"
4 - Click "Add Db" to create the database
5 - Look where it says "Users" (It should be right under the database creation section)
6 - Type in your desired username in the textbox that correspends to "UserName:"
7 - Type in your desired password in the textbox that corresponds to "Password:"
8 - Click "Add User" to create the username
Now that you have your database and username created, you will have to add the username to the database, please read below:
1 - Look in the top where it has a button saying "Add User to Db"
2 - In the left dropbox corresponding to "User:" you must select the username you created in the first few steps mentioned above
3 - In the right dropbox corresponding to "Db:" you must select the database you created in the first few steps which were also mentioned above
4 - Once you have selected the username and database, you will have to click the button saying "Add User to Db"
????: NamePros.com http://www.namepros.com/webmaster-tutorials/108916-mysql-database-tutorial-adding-username-database.html
Now that you have everything done, it is time to install the script
Host - localhost
Database Name - "cPanelUsername"_DatabaseName
Username - "cPanelUsername"_Username
Password - Password
I hope that briefly explains how to create a database and username and add a specific username to a specific database
NOTE: This tutorial is for learning purposes only

If you plan to distribute this tutorial or add this tutorial to your website, please let me know before you do so