All files and folders should go under the public_html directory.
Please be sure to create an index file for your first page. This can be index.htm, index.html, index.php, etc. Our system looks for those exact names by default. It must be placed directly under public_html and not a subfolder. When you go to http://yourdomain.com, this file will then automatically open. Without it, your file structure will show instead.
For subdomains and other folders, when going to the folders at http://sub.yourdomain.com or http://yourdomain.com/folder/ an index file in them will behave the same way and automatically open.
index.htm and Index.htm are two separate files. Index.htm will not be recognized as the default first page.