1. The first thing for you to do is to switch off the device.
2. Press and hold the Power & Volume buttons for five seconds or so, until an Android logo appears.
3. Let go of buttons held when an Android logo comes on screen.
4. Using Volume Up to scroll down and Volume Down to choose the option, select Recovery Mode.
5. Good job, you are in Recovery mode. Navigate it with Volume Up; select options with Volume Down.