There are many uses for WordPress Multisite but it is seldom adopted from the outset. As a method to administer multiple sites under a single network it is unparalleled but where it is used mostly is for multilingual versions of the same site.
The majority of WordPress administrators begin the process of making their site into a multilingual instance with one of the many excellent plugins available on WordPress (WPML, Weglot, Polylang etc.) after they have launched their default language version.
This is understandable - it is a quick and easy way to adopt an alternative language version of your site. There is a point however when many site managers will out-grow this approach and are then left with the task of creating a multi-site from a single instance data-set.
Here are some tips to consider if you find yourself with this challenging task:
Multi-site shares the one database & file-system but the sub-sites are isolated with new core db tables. Here is a example of how the wp_options table will appear after generating the first sub-site: www_2_options
If you can understand this principle you have overcome the first major hurdle. Adopting Multisite is essentially a data management task where you are using a base data-set to create further versions while sharing the same WordPress core code framework.
If this is making your head spin however, feel free to Contact Us! We are happy to share our insights and help anyone along the way to adopt the great WordPress feature.