Yeah @kurulumu-Net you can change port in config.json in one of the NodeBBs and change to the same port in the proxy-pass part of the corresponding nginx config.
Default port is 4567, one will need to be changed.
We created a new category specifically for guides and general tips and tricks.
There's a bunch of good resources in other categories that we'll be moving here over time, but any new tutorials would totally be appreciated.
Please try to post the version of NodeBB that you based your guide on. Thanks!