Apache isn't the only technology that is capable of allowing you to host web content on your server. NGINX also serves the same purpose and is gaining popularity quite rapidly. Although Apache is still the most common right now and is what I recommend for hosting sites, it's a good idea to at least be familiar with NGINX and learn its basics.
Before we do so, I want to mention first that you can really only have one web server service running on a single web server. If you've been following along up to now, you currently have a functional Apache web server. If you were to also install NGINX, it probably wouldn't start as the ports it wants to listen on (port 80 and/or 443) will already be in use. You can run both on a single server, but that's outside the scope of this book. Ideally, you'd want to use one or the other...