How do I create a public category?
Simply make sure the "Show on my profile" checkbox is ticked, and the "Private" checkbox isn't.
Where is the "Show on my Profile" box? I can't find anything like that when I go to the edit page of my game.
That checkbox is is visible in your library, and refers to categories. To control which games are visible on your creator profile, use the theme editor.
The only thing I can see in my library is a list of games I've rated. I don't see that check box anywhere.
Perhaps because you haven't created any collections yet. Try it.
Edit: oops, I kept saying "categories" so far. They're collections.