I have just suceeded to take root privilede on Samsung Galsxy S6 (Global Model, SM-G920F), Android Version 7.0(G920FXXU6ERF5), after some struggles.

These easy ways did not work in the first place.

1. One click root: it stacked at "no internet connection", even though it has. (maybe it is inside of an intranet, and no direct connection was possible. a proxy was required.)
2. pingpong root: it failed to install SU.

I used the method using ODDIN and TWRP with SU intallation.

1. Preparation on the phone.
   1. make Developper's mode appear (tap "build" 7 times)
   2. enable usb-debugging mode.
   3. NO to "enable EMS overide." on G920F(global model).
2. download supersu: N920_Nougat_Root_SuperSU_No_kernel_included.zip.
3. shutdown your device. Boot into "download" mode by keeping pushing volume-down, home and power buttons at the same time. then press Volume-up to confirm.
4. Flush the TWRP into your device by using oddin. (see details below).
5. boot into TWRP. (see details below).
6. press "install" and find the supersu. Voilla!

The Keys to scuccess: Use the proper versions, and take proper procedures.

• proper versions for Galaxy S6 SM-G920F:
It took unnecessarily long time because I used a wrong version.
1. odin: oddin3_3.12.3.zip.
2. twrp: twrp-3.1.0-0-zeroflt.zip (this is for S6.)
3. supersu: N920_Nougat_Root_SuperSU_No_kernel_included.zip.
• proper procedure
Read carefully. I did some wrong procedures, something similar to below, which did not work.
1. from odin: options tab -> make sure a tick only on F.Reset Time and no tick on Auto Reboot. Press AP button and choose the twrp mentioned above.
2. after flush the twrp, do NOT reboot. But press volume-down, home and power. Once screen turns black, slide your finger from volume-down to volume up. Thus you push volume-up, home and power. By this, twrp successfully booted up, finally.
3. you have to install supersu at this timing, without which you will enter galaxy-s6 logo infinite loop. If you did not download the file, you can copy from your computer. (that is how I solved the problem).
4. Also I had a problem of "no command" after flushing twrp. (No TWRP boot). If you have the same problem, please read the procedure and versions above carefully. It may solve your problem, too!