You will need to log into cPanel with your supplied username and password. Normally this URL is: http://www.yourdomain.com/cpanel
1) Select the Username field and enter your username
2) Select the Password field and enter your password
3) Next click the Log in button
4) Select the phpMyAdmin icon from the Databases section
5) Select the database you wish to restore
6) Scroll down and select the Check All link
7) Now click the With selected dropdown list and choose Empty
8) Scroll down and click the Yes button
This empties all our tables
9) Now click on the Import tab
10) Click the browse button
11) Select our backup file previously created using phpMyAdmin
12) Click the Open button
13) Scroll down and click the Go button
You now know how to restore a Joomla backup using phpMyAdmin