1. First of all, turn the device off by holding down the Power key.
2. Now press & hold the Volume Down + Power button for a while.
3. You can release held buttons when an Asus logo shows on screen.
4. Press Volume Down to choose Recovery option. Confirm the choice with Power button.
5. Press and hold Power button as soon as the Android logo appears on screen.
6. Done, you're in the Recovery Mode.
7. Scroll through the options using Volume buttons; select them with the Power button.