A great feature of the 3rd generation Apple TV that’s described in an Apple support document:
Connect your Apple TV to your television and power and wait until your Apple TV displays the setup screen.
Unlock your iOS 7 device and ensure that Bluetooth is enabled. Also ensure that you are connected to the Wi-Fi network you want to use with Apple TV.
Touch your iOS device to your Apple TV and wait for the prompts to appear on your iOS device and Apple TV.