Each of your assignments should be placed in your server in folders named "assignment1", "assignment2", etc. This way, when we go to grade projects, we can just head to yourdomain.mynmi.new/assignment1 and not have to hunt around for differently-named projects.
In HTML (and CSS, and JS, for that matter), file names are case sensitive, meaning that File.html and file.html are two different files.
You also should avoid spaces and most punctuation. Even though Finder will handle these just fine, they might cause some problems with certain OSes and web browsers.
Finally, there's one magic file name in HTML: index.html. In any given folder, a web browser will first look for and open index.html. This means that if you point a web browser to example.mynmi.net, the browser will check to see if there's a file at example.mynmi.net/index.html, and if there is, it'll open it.
Why does this matter? For all of your assignments [footnote]Except for anything involving WordPress—it takes care of this stuff for you[/footnote] for this class, be sure to name the main page of each project index.html.
Developers will get into huge arguments about how, exactly, you should do this, but the essential thing is that whether you're writing HTML or CSS, you consistently indent your code.
Why? To save your future self from misery. When it comes time to find an error, your life will be infinitely easier if all your work is clearly and consistently indented.