1) Download the update.zip file here - LINK
2) Now copy this update.zip file directly in your phone’s SD Card not inside any folder.
3) Switch off your device and restart it into recovery mode using the following key combination.
(Volume UP + Home Button + Power Button)
4)You cannot use touchscreen while your phone is in recovery mode.
For making selections or movements, use of volume up/down keys and for selection use the home key.
5) In the recovery mode menu, there is an option 'apply update from sdcard' Select it.
6) Choose update.zip and click on “yes”.
7) After the patching, you will go back to the RECOVERY main menu, then choose “reboot system now”.
8) After the reboot, go to the phone's main menu, when you fine the application "SUPERUSER" that means your device is successfully rooted.
This is only for educational purposes and I will not be responsible for any damages that may happen on your device. Do it on your own risk.