^ This works!
I successfully rooted my Galaxy Express Prime (AT&T GoPhone, Marshmallow 6.01) using the file attached in the video and Odin v3.11.
Direct link to file to skip all the ad BS (you're welcome):
http://down1.dailyuploads.net:182/d...a5xjlwzjrxjcimhwaeflzovjlbsl3s/Root_J320A.zip
Odin v3.11:
https://odindownload.com/download/Odin3_v3.11.1.zip
Samsung Android USB Driver:
Android USB Driver for Windows | SAMSUNG Developers
1.) Turn your phone off
2.) Hold down Vol - / Home / PWR to boot into Download Mode
3.) Sync phone with PC (make sure Windows recognizes it in DL mode or Odin won't recognize it)
4.) Extract .zip file to destination of your choice
5.) Open Odin, click AP, target /bin/sm-j320a_Engroot_601PJ2
6.) From Odin, Hit the start button. It should only take 4-5 seconds to flash your phone and reboot
7.) After your phone restarts - Settings -> Enable ADB, USB debugging, OEM Unlock (not sure if it did anything)
8.) Run the root.bat file
If all goes well, congrats. You now have a rooted SM-J320A
It worked for me and it should work for you too! Good luck.