Simple steps to create multisite from singlesite.
To enable Multisite, you need to access your site using an FTP client or cPanel file manager and open wp-config.php file for editing.
You need to add this line to your wp-config.php file just before the /* That’s all, stop editing! Happy blogging. */ line.
/* Multisite */
define( ‘WP_ALLOW_MULTISITE’, true );
Save and upload your wp-config.php file back to the server. Now your WordPress site supports multisite network.
Deactivate all plugins on your single site installation.
Go to tools -> Network setup to configure your network.
The most important option here will be the choice. It’s more from SEO point of view:
- create new sites by subdomain – each site separate for SEO purposes.
- create new sites as sub-directories – SEO juice stays in the whole website.
It’s worth that you search other peoples opinions on this subject as it may be an important choice. Personally I am choosing sub-directories.
WordPress provide you on the next screen with extra code which has to be pasted into wp-config and .htaccess
These are 4 simple steps but for more info you could check the below articles: