Make iCloud document folder as the local document folder

Hi all,

In my older devices (MacBook and iMac), I do not have a local document folder. When I choose to synchronize my iCloud, the "Document" folder in my iCloud is automatically my local one.

However, in my new MacBook Air I just got, after I log in my iCloud and choose to synchronize, the default "Document" folder is a local one, and it is separate from another "Document" folder in my iCloud.

This is rather inconvenient for me if I want to open the "Document" folder in iCloud from my terminal or other apps such as Emacs. In the past, since the iCloud document is the same as the local one, I can just open the folder locally. But now if I open the local document folder, it is an empty one just for the local system.

My question is: how to make the local "Document" folder the same as the "Document" in iCloud? (I would like to make them the same one, if possible, instead of copying files from one to the other.)