...
Site-switching links let users jump between different sites within your multi-site platform. Links can be in different locations on each site, but we recommend being consistent so that users know what to expect. Add links to:
The More menu. This is the best way to make sure people can consistently find other sites.
Modules. This is a great way to advertise another site. For example, create a banner ad or pull a piece of content (like a session) from another site.
If you don’t want users to switch sites, you can remove the link. Or just hide it from users without the right access level.
...
Check out these articles to start thinking about what will be the same and what will be different on each of your sites:
https://help.growthzone.com/clients/configure-pages-and-Navigation options
Special configuration: Seasonal looks or brand campaigns
...