how to create a playgroundbook in mac swiftplayground ?

Download the Xcode11.1 project from https://developer.apple.com/download/more/?=Swift%20Playgrounds%20Author%20Template .Build it on Xcode 11.1 and drag your .playground book in the products folder into Finder. Upload the .playgroundbook file.

I learnt from this ,

https://www.freecodecamp.org/news/how-to-make-something-with-swift-playgrounds-33e560b84184/

11.4.1, actually.

If you are creating .playground for Xcode Playground, you need to use Xcode 11.4.1.

Are you going to create a .playgroundbook or a .playground ?

Isn't a .playgroundbook automatically created when you start a new playground in the Swift Playgrounds app?

You can create a playground book on Xcode 11.1 and then export the .playground book. You are allowed to submit the .playgroundbook as long as it works on Swift Playgrounds 3.3