Most probably you have been wondering how the Webserver decides which page from your site to use as a main/default page of your site. There is a directive named DirectoryIndex which takes care of this.
On most web servers there is a pre-defined set of file names which server a start page.
The most commonly used are: index.html, default.html, index.php, index.asp, etc.
The good news is that you can set your custom file to be a start page of your site using .htaccess.
For example the following line set home-page.html as a main page of your site:
DirectoryIndex home-page.html
The DirectoryIndex directive can accept more than one name:
DirectoryIndex home-page.html Home.html, index.html index.php index.cgi
So when a visitors goes to http://www.example.com the first page to be loaded will be the home-page.html if it cannot be found the server will look then for Home.html, index.html, etc until it finds a match.