Thanks to both of you. I already have an "index.html" file (that's the one that shows up as the HOME page online and where incoming visitors are defaulted to, and whose associated files are in the "HOME_files" folder).
I've googled ".htaccess file" and there seems to be plenty of information on the subject. I've frankly never heard of such a thing before. I'm going to see if there's a tutorial online here are DreamHost as well. However, if you have any pointers, simple hints, anything to flatten the learning curve feel free to share.