Demonstrates: an old page kept in oldpublic/. It is listed on /all. Old pages with fewer than 100 words, folder listings, redirects and copies are published too, but left out of lists.
Apache is a web server. On Debian, install it with the package manager: sudo apt-get update, then sudo apt-get install apache2. Open http://localhost in a browser, and you see the default page. Your own pages go to /var/www/html/. Replace index.html there with your own page, then reload the browser to see it. If the page doesn't change, read the end of the error log in /var/log/apache2/error.log to find out why. When it works, try the same with a name based virtual host.