1) In cPanel select the link "MySQL Databases."
2) In the "Db:" section specify a name for the database that you are creating (ex: store, forum, etc..). After you have specified the name click "Add Db" and the database will be created.
3) In the "Users:" section specify a "Username," & "Password" for the database that you are creating (Note: you may use the same User/Password for all of your Databases).
4) At the bottom of the "Databases:" section you will now see "User: (username_yourname)," "Db: (username_databasename)." Select the "User" from the left dropdown menu and "Db" from the right dropdown menu that you want to use. "Click Add User to Db."
After your database is created you can manage it from phpmyadmin. This can be found at the very bottom of the MySQL page.