If you see Connect to iTunes screen when you start iPhone, iPad, or iPod touch
In some situations, you might see the Connect to iTunes screen when you start your iPhone, iPad, or iPod touch. When this happens, your device is in recovery mode. Here's what to do.
Restart your device by pressing and holding the Sleep/Wake and Home buttons at the same time until you see the Apple logo.
If you see the Connect to iTunes screen again, you'll need to reinstall iOS. Follow these steps:
1. Connect your device to your computer.
2. You should see this message: "The software on [your device name] needs to be restored to factory settings or updated."
3. Click Update to reinstall iOS while keeping your data.
Get help if, after following the steps above, you see a restore error.
If you don't see a restore error, but you still see the Connect to iTunes screen when you start your device, contact Apple.
Source - https://support.apple.com/en-gb/HT203122