How to enable “sites” feature for members

I see that there is a tab called “Sites” on member’s profile page on theme demo For example : https://seventhqueen.com/themes/kleo/members/demo/blogs/

I don’t even see how to add a site in this demo account. I see that you can add multiple sites for example here: https://seventhqueen.com/themes/kleo/members/kleoadmin/blogs/

I couldn’t get anything in the documentation. Please guide how to bring this feature and how does it work?

Thanks