I’ve done this a few times so I know the pitfalls. I followed the instructions at https://wpmudev.com/wpmu-manual/creating-a-network-to-enable-wordpress-multisite/ exactly step by step making sure to type the define(‘WP_ALLOW_MULTISITE’, true); code instead of pasting it in. And yet when I log out and log back in, there is no Network Setup under the Tools. I even tried deleting the existing wp-config.php file then uploading the edited one and that did not work. I am baffled as to why it is not taking.