Changine ports from 80 443 to SOMETHING Else

I am a newbie with enough knowledge about networks to understand that I am ignorant to webservers

I just installed ubuntu server and int he process I installed as a “SNAP” nextcloud. this was done on a clean machine (stand alone)

The issue is that I have a web server running behind my linksys router that already uses ports 80 and 443.

I wanted to point the NEXTCLOUD out so that I can access it from the internet. I am using NO IP to create a DNS link. the issue is that if I go to the link I get my webserver because it already using the ports 80 and 443.

the documents I have found tell me that I can change the ports on Next cloud, the issue I run into is that all the files are read only in the SNAP. I have seen a suggestion that i should use some sort of port forwarding string in my IP tables, I do not understand what this means.

Even as I write this, there is an article that is similar, but it does not answer my question as the files referenced in that topic do not exist.

What you need is a (Nginx) Reverse Proxy to be able to run the same ports to different backend servers or serivces on one public IP.

There are a lot of information regarding it online and if you want to try it yourself, here is a guide.

Or if you want to get hands on support, you can do so here.