NOTICE:
All your internal phone storage data will be lose!!
Make this action with your own risk!!.
1.Power off your phone
2.Hold the x keys from the keyboard and press the power on button.
3.Once the bootloaders already shown up press the volume up button with the camera button at the same times,till you se the recovery menu.
4.Navigate to the wipe data / factory default then press power button
5.Wait the process till completly finish then reboot your device.
You also can see this video tutorial how to perform the hard reset action.