Multisite is a WordPress feature which allows users to create a network of sites on a single WordPress installation. Available since WordPress version 3.0, Multisite is a continuation of WPMU or WordPress Multiuser project.
The first thing you need to do is to install WordPress. After that connect to your website using an FTP client like FileZilla.
Edit the file, wp-config.php
and add the following line just before "That’s all, stop editing! Happy blogging".
/* Multisite */
Save your wp-config.php file and log in to your WordPress website. Go to Tools » Network Setup. This is the place where you will configure and set up your WordPress Multisite Network:
On the network set up screen, you need to choose whether you want network sites to be on their own subdomains or sub-directories. Choose wisely because you can not change it later. If you choose subdomains, then you will have to change your DNS settings for domain mapping. We will get to that part later.
In the network details section, give your network a name and an admin address. Click on Install button.
On the next screen, WordPress will provide you with some code that you need to add to wp-config.php and .htaccess file. Both files are located in your WordPress root directory. Connect to your website using an FTP client and open these files and paste the code provided by WordPress.
Once you have successfully updated both files. You will have to log in again to your WordPress admin area. After the login, you will see WordPress Multisite Network menu on top of the WordPress admin bar.
Take your mouse over to My Sites in WordPress admin bar and then click on Dashboard. This is the dashboard for your Multisite network. You can add or delete sites, install plugins and themes, and manage users from here.
To manage your Multisite network settings. Go to Settings » Network Settings. This is the page where you can open up your website for registration. You can allow users to create accounts and create sites. However, you can leave registration disabled if you want to manually add users and sites yourself.
Among other settings, you can edit the emails sent by WordPress when a user creates a new site. You can change the text of default post, page and comment added by WordPress on new sites. Just remember that the settings here will affect all sites and users on your website so you need to be careful.
Sites in a Multisite WordPress can be managed from Sites screen under the Multisite Dashboard. Among these settings, you can not only add or delete, but also deactivate and archive sites.
When a Multisite site is deactivated, it becomes invisible to the visitors and the site admin as well. An archived site is visible only to Super Admin. The Super Admin can also mark a site as spam, which will make the site invisible to everyone, including the site admin. Deleting a site permanently removes it from the network.