First attempt at MOC - confused.

So I was cleaning up my vault and consolidating topics and notes. Then I fell into the rabbit of hole of Obsidian on Youtube... came across the Map of Contents / Index.

I download Map of and DataView.
I made a Main Note titled it _Map of Content and selected it. I did NOT add any folders to exclude.
I have notes in folders of the topic they are covering, and pretty much trying to add the folder so all the notes would be displayed. However when I drag and drop the folder nothing happens.
I can select note by note, and drag and drop it, but this seems like bit counterproductive.

I do use the JD folder system for Main Topics. So its somewhat organized, but always looking to pivot/try something new to see if something works better.

I just thought I would be able to drag a folder over into the note and it would show all the notes inside.
I am running obsidian on EndeavourOS KDE system up to date as for tonight.

I just feel like I am missing something...