ENG (AP) files for S7 and S7E
This is the ENGINEER boot kernel boot.tar file you'll be flashing in the special modified Odin software from your PC
https://www.androidfilehost.com/?fid=457095661767141717
SuperSU 2.79 root.bat file
This is the command prompt script you'll execute from a CMD prompt from a windows PC that installs the needed files for root access like SuperSU
https://www.androidfilehost.com/?fid=817550096634750763
After Eng-Boot (root is complete)
After all process return to STOCK Android 7.0 Nougat
You will need to have Odin installed (same modified Odin linked above should work fine)
You can download stock Android 7.0 Nougat firmware