Multiple Scenes (Windows)

It appears, scenes are represented as windows on macOS. It looks like I can use @SceneBuilder to compose multiple scenes in my @main App. The Settings Scene that comes with SwiftUI is an example of a window that is not displayed/presented until the command is invoked from the menu. Can I do the same with my own custom scenes? How would I present it in response to the tap of a button? Is there a way to share data between them?
I would love to get an answer to this question as well. For instance, on iOS, can I choose when to present my DocumentGroup in a Scene? So that I can add onboarding information in a different Scene?
Multiple Scenes (Windows)
 
 
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