Participating Sites" will appear on the top toolbar, and select "Dashboard" under "Site Network Management" in it.

Plug-ins, themes, etc. are also configured here, so recognize it as the dashboard of the entire site.

Change the permission of new registration from "Site Network Settings" in "Settings".

If you allow new sites to register, you are ready to go.

When "Create a new site" is selected, the above screen will appear, so configure the settings as desired.

Select "Language" if you want to make the site multilingual.

In this case, we want to unify the multilingualization, so we also added the basic language.

The main site can be in any language.