Running a web server

I read this https://www.dyclassroom.com/howto-mac/how-to-install-apache-mysql-php-on-macos-catalina-10-15

and another a recent thread in another Apple Community forums. WHY can't i ask there?! oh well.

ALL i want is the web server, no need for php or scripts, ssl, etc. I own the domain name, already running.

everything i need to know is in the above article; EXCEPT THIS (right?):

where do i enter my domain and/or ip?

this is to run from home off my own machine (as it is now, but i want to upgrade the OS and will lose my site and the Server app -- newer server app has no web service, as you know I' am sure: MAJOR COMPLAINT! as I type from High Sierra, unable to upgrade).

Thanks

ps: why don't these articles include that? I just be missing brain cells or something.