1. Hello. Please press the Power button to turn your phone off.
2. Now press & hold the Volume Up and Power button for a few seconds.
3. Afterwards press Volume Down to select option "Recovery", and press Power button to confirm.
4. Android image will show on screen. When it does, press the Volume Up and Power buttons for a few seconds.
5. Good job, you are in Recovery mode. Navigate it with Volume buttons; select options with Power button.