Where does the doc notebook exist?

Translation: Hello, in cloud sync, it is observable that there are notes in the document. Therefore, they should also be visible in the doc notebook (but the doc notebook appears empty, as seen in the second screenshot).

However, notes made on the document on an iPad can be synced to a Mac. The issue is that they cannot be seen in the doc notebook, which means they cannot be managed.

Is this normal? What could be the reason?

Additionally, if I have two versions of the same note, will it generate two doc notebooks?

Lastly, where is the doc notebook located on a Mac?

Thank you!