1. First of all, turn the device off by holding down the Power key.
2. Power button, after a few seconds, need to be pressed again.
3. Press & hold Volume Up and Volume Down buttons for about five seconds.
4. Release held keys when the Android logo appears.
5. Now you must select the Recovery option. Use Volume Up and Volume Down keys to navigate and press Power button to select it.
6. Unless you messed something up, you're now in the Recovery Mode.