The video did it wrong too.
If you read carefully there are steps in original post how to install the rom:
* TWRP Recovery Zip DOWNLOAD or TWRP.ME
* FORMAT /data partition (NEVER wipe System or Persist!)
* Copy our ROM to the internal storage
* Install our ROM
* Reboot
* done
After twrp flashing go to wipe -> format data and yes and restart twrp, then transfer the rom to internal storage and flash it and reboot. You did it wrong I'm afraid.