WordPress Multi level blog

WordPress.org Tutorial

First you need to add the following line into wp-config.php just before /* That’s all, stop editing! Happy blogging. */

define('WP_ALLOW_MULTISITE', true);

Then Reload your wordpress admin page

Under Tools menu, now you can see the Network menu

Click on the Network link and follow the instruction on the page, then the WordPress Blog system is multi level, multi user enable.