If you use iTunes to back up data, you also need to use iTunes to restore backup. If you use Finder to back up data, please use Finder to restore.
Step 1: Connect your device to your computer via USB cables.
Step 2: Enter your devices passcode to "Trust This Computer" on your iPhone or iPad.
Step 3: Find your device on iTunes or Finder.
If your devices don't appear, replug cables serveral times to try or using other USB port to see whether they can work.
Step 4: Select "Restore Backup".
Stpe 5: Pick one backup to restore if you have different backup.
Step 6: Click "Restore" and wait for it to finish.
If asked, please enter your password for your encrypted backup. Stay your devices connected to computers until the process finishes and you are able to disconnect.
Note: If you have any doubt for restoring backup, please check Apple support and contact Apple customer service to get help.