Sorry but another reverse proxy question

[Manxman]

I have spent weeks trying to get a reverse proxy setup working as we travel a lot so want access to imatch from our motorhome on Android and Apple devices. I have tried Apache, Nginx, IIS and other possible approaches but never with success.

I regularly get the imatch basic screen but no further when outside the local network.  The json file has been edited with the ip address. From all my reading that is the only change needed from the imatch side.

Is there a detailed walk through or instruction article available which can help?

Thanks in advance.