New "preview" videos allow developers to visually show an app's function. After the update installs and your device restarts, you can slide to set up iOS 8. Be patient and use the time to get your devices prepared for iOS 8 , namely backing up your devices and creating enough space to download the update. A new Tap to Talk chat button lets users send quick voice comments to a recipient, and a Record button allows users to record short videos. No need for a computer or iTunes. Users can enter their medical history in Medical ID, which is accessible on the lock screen, in case of an emergency.