1. Follow all the preinstall steps from here.
  2. Install a custom recovery for your device. Choose one from here. Currently, A72 is not supported.
  3. Copy the zip to either internal storage or SD card. Alternatively, use adb sideload.
  4. OPTIONAL but recommended: Format data in the "Wipe" menu in recovery. This will erase media too.
  5. Flash the zip in recovery and follow the on-screen instructions.
  6. After the first flash is complete, you need to confirm by pressing one of the Volume buttons.
  7. Your phone will again reboot to recovery.
  8. Flash the ROM again and select your preferred CSC features.
  9. Once the installation is done, reboot your phone.
  10. If you did everything correctly then your phone will reboot into NcX.
  11. If it does not boot, flash the full stock ROM with Odin.