1. Open iTunes on your PC or Mac. If you can't access a computer, you can erase and restore your device without a computer.
2. Connect your iPhone, iPad, or iPod to your computer with the cable that came with your device.
3. If a message asks for your device passcode or to Trust This Computer
4. Select your iPhone, iPad, or iPod when it appears in iTunes.
5. In the Summary panel, click Restore [device].
6. Click Restore again to confirm. Then iTunes erases your device and installs the latest iOS or iPod software.
7. After your device restores to factory settings, it restarts.
8. Now you can set it up as new.