The following article will explain how to turn on Multisite mode at wordpress site:
- Open wp-config.php file for editing.
- Locate /* That's all, stop editing! Happy blogging. */
- Add before it:
- define( 'WP_ALLOW_MULTISITE', true );
- Logout and login again to wordpress site.
- Browse to Dashboard.
- Under Tools select “Network”
- Follow instructions there.