How do you build a country in the 1920's era when the people were already an established nation?

So the basic idea was to do a country build where they were a group of people with their own language and culture and floating island with a town from 1920's in the middle of the Atlantic. It's kind of a mystical island, the people in the town are aware of the rest of the world and their island can move so that they can travel. They have their own government which has been established for over a century since they moved to the island.<br><br>But when I was building it, I realized that it's a town and not necessarily a country. The town is pretty much isolated from the rest of the world, so not many people are aware of it. The people don't really have access to the outside world, so they don't really know much about what's going on. They don't really know the nations in the rest of the world, so it's not really a country in the conventional sense. I realize now that having an island with a town that floats around and the people are aware of the rest of the world, but not really the rest of the world is aware of them, is a really hard concept to build a country around because it's not really a country.<br><br>I decided to do a nation build instead, but I had no idea where to start. They have a town, people and island, and I know that they have their own language, but I was really stuck on how to turn it into a nation. I have some ideas for a national holiday and a sort of "national pastime" that's based on a different holiday, but I still feel really stuck. I have a hard time building in general, but this was much worse.<br><br>So how do you build a country when you have an established nation? I think a lot of people here have done that kind of thing and I would love to hear how you did it.<br><br>tl;dr: I was trying to build a country and got really stuck, has anyone else had this problem? How did you build your floating island nation?