Changing The Default Page using .htaccess
If you are unable to edit your master configuration files, you can use this directive from .htaccess. Just edit the .htaccess file located in your main HTML directory. If you do not have this file, feel free to create it!
To change the default page, either edit the existingDirectoryIndex line or add the following:
DirectoryIndex index.shtml index.html
This will make index.shtml the default page.
By using a .htaccess file in a subdirectory, you can specify a different default page for that one directory without affecting the rest of your site.