I don’t know what YouTube video you’re referring to, or the CSS Tricks article it was based on (plus the code provided is a bit mangled and looks incomplete) but it sounds like you need to research more about the simpleXML extension in PHP. Once you understand how to use that you’ll be able to manipulate the code to your own needs and display the feed however you want in your web page. I did a basic blog post here which you can refer to to get started http://blog.fofwebdesign.co.uk/25-xml-to-html-getting-xml-data-into-a-web-page-with-simplexml but you can Google something like “RSS to web page using PHP simpleXML” for lots more tutorials. Try working through them and see what you come up with.
Good luck with your project.