include blog on main page

To turn a regular php document into a WordPress one, just add this to the very top:
<?php
require_once('./wp-blog-header.php');
?>
If your blog is in a subdirectory (i.e. /blog) to your main page, make sure it reflects that:
<?php
require_once('./blog/wp-blog-header.php');
?>
Then you can insert any WordPress template tags you’d like.