Port Forwarding

I have seen many complaints on this one and I dont think xfinity understands that the scripts dont work and the app is broke. Does anyone know how to port forward. When I log into the router the port forwarding tab sends me to the xfinity page and tells me to download the app but there is no place in the app to setup port forwarding. I also saw on reddit other people saying to use a chat bot in the app to setup port forwarding but I guess xfinity took that away too. What gives!? How can I port forward on this over priced turd I have to rent from a place with little to no support?!