I want to bulk change the "type" in many folders

[FearlessFrd]

I'm wanting to bulk change the "type" from "music" to "audiobooks" for many folders and sub folders.
The only way I can see to do this is to go into each audio book within it's own folder and change the file properties item. I can't select properties from any folder.
As I have many audiobooks I'm wanting to change this is extremely laborious - is there any way to do this in bulk?

[FearlessFrd]

I actually managed to do this but unfortunately can't really explain how in detail - I basically changed the views, then managed to see and select all the files, which then allowed them all to be changed from music to audiobooks.

[sfghryjytjt]

on the toolbar in the top right click display folder content recursively, then it will also show sub folders files as well