Downloads:
*Odin 3 v3.0.9
*CWM recovery thread(Downloads available for 4.3 and 4.4 also)
*SuperSU
Steps to root your phone:
1) Download the first two files given above to your laptop/PC.
2) Turn off your phone.
3) Go to download mode (by pressing Vol.down+home+power buttons at the same time for about 7-8 secs)
4)Open the ODIN file you downloaded on your laptop/pc.
5) Connect your phone to your laptop/PC through USB cable.
6) When ODIN detects your phone, the ID:COM area will become yellow/blue
7) In ODIN click on PDA and then select the recovery file you downloaded. Also tick the check box beside PDA(if there is any)
8) Click on start. The flashing process will start.
9) If the flashing succeeds, ODIN will show 'PASS'. That means the recovery flashed successfully. Yay!!!
10) Now turn on your phone and download the third file and place it in your external SD card.
11) Turn off your phone.
12) Reboot to recovery(by pressing Vol.up+home+power buttons).
13) The recovery will start. You have to navigate by volume buttons and power button.
Vol.up - move up
Vol.down - move down
Power button - select option
14) Select 'install zip'.
15) Select 'Choose zip from ext_sd or external SD card'.
16)Select the third file you downloaded. Flashing process will start.
17) After it finishes, go back and reboot your phone.
It's upon you, of you want to follow this:
18)Use Knox Remover to remove all Knox files.