A hard reset, also known as a factory reset or master reset, is the restoration of a device to the state it was in when it left the factory. All settings, applications and data added by the user are removed.
To perform hard reset on your device you will have to do these simple steps:
1. Turn off your device
2. Now press and hold volume down + home + power buttons and wait for the phones vibration, otherwise dont let go off the buttons.
3. Next thing that should appear is this screen:
4. Please navigate with volume keys and confirm with Power button on wipe data/factory reset.
5. Now your device will reset and restart. Congratulations