SuperSU Installation Tutorial for Samsung G900I
（1）Rooting will void your phone warranty and you won’t get it back.
（2）Follow the steps properly; otherwise, you may damage your device. We are not responsible for any damage of your phone.
（3）It will erase all your personal data, including data of internal storage, so we advise you to take a complete backup of your phone before proceeding.
（4）Make sure that your phone has at least 50-60% of battery available to prevent the accidental shutdown in-between the process.
Enable the ‘USB debugging’ and ‘OEM Unlock’ options from Settings>Developer Options>. To enable Developer Options, go to About phone and tap Build Number 7 times. Connect your phone to the PC.
Download the SuperSU.zip on your PC and copy it to your phone's SD card.
Download and install Samsung Galaxy USB Driverson on your PC .
Download the Latest Odin Tool on your PC and extract the zip file.
Download the Official TWRP Recovery for Samsung Galaxy G900I on your PC and extract the zip file.
Steps to Root and install TWRP Recovery on a Samsung Galaxy G900I
(1) Plug the USB to the computer.
(2) Transfer the UPDATE-SuperSU-v2.76.zip to your Galaxy G900I (you can choose either your internal or external storage. I, personally, prefer the internal storage). Don't unzip it; transfer the zip file!
(3) Enter your phone into "Download Mode". Power off your phone, press the volume down, home button and power button.
(4) You should now see "Warning". Press the volume up button to continue.
(5) Unzip Odin3_v184.108.40.206zip and run odin3 v220.127.116.11.exe.
(6) You should see a yellow box on the left side of Odin. If you can't see it, install the Samsung USB driver, reboot your computer and run Odin.
(7) Uncheck "Auto Reboot".
(8) Locate and add the twrp-3.0.0-xxx.img.tar file (you downloaded it from above) to the AP/PDA tab in Odin.
(9) Click on "Start"; this will only take a few seconds. Odin will show "PASS!" in green. Congrats, now you have PhilZ Touch Recovery installed. But we still need to root your device ( and get SuperSU access).
(10) Unplug your phone and enter into recovery mode. Press and hold the volume up, home button and power button, all at the same time. Hold them for about 15 seconds.
(11) You should now see a pink/purple interface. Select "Install Zip".
(12) Select "Choose zip from /sdcard".
(13) Locate UPDATE-SuperSU-v2.76.zip, select it, and click "yes".
(14) We're almost done! Select any key at the bottom of the screen, choose "+++++Go Back++++++" and click "Reboot System Now".
(15) You should already have SuperSU installed in your app drawer. Open the app and select "Ok", when being asked to disable KNOX.
(16) We are done! Your Galaxy G900I is completely rooted.