On the very beginning you should switch off your device by holding down the Power key.
Afterwards, you have to push Volume Up + Power buttons together till the Android logo icon will appear.
Now, when you are in the Recovery Mode menu you have to scroll down by using Volume buttons and choose "wipe data/factory reset" by pushing the Power key.
Then go down and choose "Yes" to complete the whole operation.
When the menu will appear again you have to choose "reboot system now".
Excellent! The hard reset operation had been perfomed successfully!
