Port forwarding

I'm totaly new to Sophos UTM 9 but I have managed to get most things working except a simple Port Forwarding.

I have a server in my network that I need to access it's webserver from the "the outside". I want to forward port 5080 (from the "outside") to port 80 on my server. Tried to follow this guide without any success:

https://fortwayneits.zendesk.com/hc/en-us/articles/235945188-How-to-do-Port-Forward-Translation-for-RDP-in-a-Sophos-UTM-9 

Can someone please help?

/Johan