I do know that you can name a directory using the _DIRECTORY %album% which is great, but is there please a way that I can create the main directory of the album artist name and then create a subdirectory within that directory of the album name
It depends a little on how your current structure looks like.
Scenario 1: you already have all the files in separate folders but you want to rename those particular folders so that further data is added (even another layer of folders).
Then use "Format value" for _DIRECTORY with an absolute path like
Format string: d:\mymusic\%albumartist%\%album%
Please note that this action does not include the filename part.
The current folder will be renamed and takes all files in it to the new location. No empty folders will remain.
Scenario 2: you still have to distribute all the files to separate folders plus rename the files.
In this case use Format value for _FILENAME
Format string: d:\mymusic\%albumartist%\%album%\$num(%track%,2) _ %title%
This will move all the selected files to the specified folder. The old folder stays where it is, even if it is empty now.
Not the whole truth.
Parent- and grandparent-directories and great-grandparents-directories and ...will remain even if they are empty after the action.
But this is not a big problem. I usually clean up after a working-session with a tool in one-go.