1. First of all, turn the device off by holding down the Power key.
2. Now press & hold the Volume Down + Power buttons for a while.
3. Menu with two options should appear before you. Let go of held keys.
4. You need to select Enter recovery mode. To do that, use Volume buttons to scroll and Power button to select.
5. Done, you're in the Recovery Mode.
6. Use Volume buttons to scroll and Power button to select options.