Need Help with WD MyCloud Port Forwarding Issue

My Cloud OS 5 Personal & Network Attached Storage My Cloud
3

Asus Support FAQ:
(Wireless Router) How to set up Virtual Server/Port Forwarding Rules on ASUS Router?

Earlier posts on port forwarding with an Asus router:
Port forwarding tutorial for a My Cloud 3TB? (FW v04.05.00-342)