My b2evolution Version: Not Entered

I need to move a blog to a sub folder but I ran into a problem.

The main docs says "edit the line at the end of the file which says: require(dirname(__FILE__)."/b2evocore/_blog_main.php");

But the php comment say

/*
* Note: if you put this file in a subdirectory, you will need to adjust the path below, for example:
* require_once dirname(__FILE__).'/../conf/_config.php';
*/
require_once dirname(__FILE__).'/conf/_config.php';

require $inc_path.'_blog_main.inc.php';
?>

I'm confused on how to add a blog into a sub folder.