Since you now have a web site on which you have posted your helloworld.html, your next step is to make a standard index.html file there.
The index.html file is your site's "home base" page. It is the file from which you will link all your expanding examples.
Start simply. Write html code in basic formats with <h1> and <p> tags, etc. Tell about your goals. Link to the helloworld.html with the <a href="helloworld.html">LINK TEXT</a> somewhere inside a paragraph.
Over time, you'll make more pages and your index page will change. Upload and overwrite with your FTP program.
In some ways, your site might be blog-like. That's OK. It probably will attract little attention until you have some wonderful content that others will flock to find.
PHP is great, but is actually a whole layer above the possible pages you can make with html all by itself. PHP is designed to create dynamic pages instead of static ones. Webcraft 101 is meant to get you to the point where you can develop static pages for a while. A lot of very useful sites are mainly static pages (you edit them at home and FTP/upload them to the site to make updates).
This comment isn't designed to get you to hold back from PHP or any other dynamic page development. The point is that you will benefit from live practice on your site with the html skills you have learned already. The more you understand and use html, the better an eventual dynamic site will be. Don't let your site be empty until you have your "Ultimate, Perfect Web App" done.
Keep at it.
B.T.W. Can you post a link to your site so we can watch your progress and cheer you on?