I'm assuming you have usb debugging, adb drivers and all set up.
- If you've set any password or pattern lock or PIN, remove it
- Download this https://drive.google.com/open?id=0B8...1JIY1B5TGpkN2M
- Extract to your desktop
- Download latest twrp 3.1.0-x . Link is available in another thread in this forum
- Place the downloaded image on your phone's internal memory
- Power off and enter fastboot mode. Connect to your PC
- Open the folder you had extracted earlier. Rename the recovery image to twrp.img
- Press shift+right click and open command window
- Execute this code
fastboot devices (to make sure if phone is being detected properly.)
fastboot boot twrp.img
Now it will boot into the recovery. The recovery is in chinese by default. In the main screen, select the sixth option which is settings, then select the rightmost tab on the next screen and change the language.
Next install the latest twrp image you had placed on phone memory earlier, select "Recovery" and reboot. You will have installed twrp permanently.
Then flash supersu 2.79 and you're set