As I mentioned, if WordPress was installed in its own directory in your public_html folder, then in a browser you would need to use //fillmorestreetfilms.com/wordpress to view it. And as you mentioned, that seemed to be working properly.
Removing the default .html file is a normal part of setting up your site. The reason you're seeing the "Index Of/" is because there is no index file present at root, and your website directories have not been protected from casual browsing yet. ( You can research that in the hosts FAQ )
If you want your WordPress site to be accessible directly from //fillmorestreetfilms.com, then install your files directly into your public_html folder, rather than inside its own folder inside of /public_html.
You might want to take some time and browse through your hosting companies FAQ, getting started, and any website/WordPress setup tutorials they offer as well.