If you are new Download the @anan1211 twrp from here:
For S7/S7E
Releases · ananjaser1211/android_device_samsung_hero
Warning make sure you dont wipe the system otherwise AnanJaser twrp will get stuck at logo! and then Flash the AJ twrp
If you also dont have the Repartitioner and cleaner download it from here:
MediaFire
flash the repartitioner and cleaner.
Clean Flash Method: Flash AnanJaser twrp Then flash the repartitioner and Then flash cleaner, Check if there is any partitions that is giving unable to mount error if there is any go to wipe > advanced wipe > click to the partition that isnt getting mounted > click to repair or change filesystem > change filesystem Click to EXT4 after that wipe vendor (if it exists there),cache,dalvik,data and then flash the rom after its done just reboot. (You can also change the data partition to F2FS For A Better & Faster Experience/Performance)