Unfortunately, the game is not being ported to mobile at the moment. I'm sorry for this inconvenience.
The app isn't only for mobile, it's for every kind of OS. So its for mobile, windows, etc.
They are talking about Itch's desktop app, though its probably better to call it a launcher.
You would have to check to be sure, but I think the game just needs to be uploaded to Itch itself rather than a third party site.