To activate an item: double tap with one finger.To hear what's directly under your finger: tap and drag your finger around the sceen.You can then use tap and swipe gestures to control the focus. When you interact with an item on the screen, a rectangular focus box will surround it.
Once Screen Reader has been activated, the process of controlling your smartphone will change, making it harder to accidentally press the screen and adding useful features for low-vision users.