Connect your device to your computer. Then select your device from the devices list, on the Summary pane, you'll see an option "restore from backup". If there's any backup available on your computer, iTunes will prompt you to choose one backup to restore.
In iTunes with your phone connected. click on iphone image in the iphone button. In the summary scroll down to Back up and restore. You will see a button that say's restore back up click on that then a drop down menu will appear. Select your back up folder and hit restore.