SOLUTION 1: If your main entry (home) page is already created but is still named default.htm, you must rename it index.htm or index.html. If you already have an index.htm or index.html page, you MUST DELETE the default.htm page before your index page will show up.
SOLUTION 2: If your index.html page is not inside public_html, it will not show up online.
I uploaded my Index.html page but all I see is a list of files and folders when I go to my web site. I can even see my Index.html in the list so I know it's in the right place!
That's your problem -- the capital "I" in Index.html (or Index.htm etc.). File names are case-sensitive. The server looks for an index.html or index.htm for its home page -- with all lowercase letters. Rename your file index.html or index.htm with all lowercase and that should make your home page visible as the home page.