Hmm... so I compared
www.timbuktufoundation.org and
www.timbuktufoundation.org/index.htm and they seem identical to me.
So the index.htm is the source code for the homepage.
I hope I am understanding your question correctly, but when you login to see all your different files and folders, look for a folder called "public_html" and then click on a file called "index.htm"
Usually, there is a default page that is pulled up one someone visits homepage (
www.timbuktufoundation.org). In this case, the default page seems to be /index.htm
I feel like this may not be answering your question, so please let me know if you're still having trouble.