You will need to log into cPanel with your supplied username and password. Normally this URL is: http://www.joomquery.com/cpanel.
Select the Username field and enter your username. Select the Password field and enter your password.
Select the phpMyAdmin icon from the Databases section. Choose the database you wish to backup if necessary.
Then click the Export tab. Using the Quick Export Method, select the Go button.
Select the Custom radio button if you wish to modify the options to the resulting backup file. Click the Save button.
Select a location on your computer to save the backup file and click the Save button.
You now know how to create a backup of your Joomla database using phpMyAdmin