You mean where to click?

In the web version of piefied.social (I don’t use mobile versions, so I won’t be able to help), try Communities-> local communities and in the new page that shows you should see a ‘Create local community’ button. Like this:

https://piefed.ca/community/add_local

It is a little bit hidden, hmm.

When you go to create a post, there are options for text, image, etc., as well as communities. Bit confusing that it’s in the same menu, but that’s how you do it.

Wait nope, that isn’t how you do it. This is just the Interstellar app being a bit weird!