Tutorial Screen Casting For IOS User

Cast video manually from iPhone or iPad
Connect your device to the same Wi-Fi network as your Apple TV, AirPlay-compatible. Find the video you want to cast.
Tap the AirPlay button, in some apps, you may need to tap a different button first. For example, in the Photos app, tap the Share button, then tap the AirPlay button choose your TV or Mac from the list.
Stream video automatically from iPhone or iPad
Depending on your AirPlay settings, your iPhone or iPad can suggest or connect automatically to devices you use regularly with AirPlay