How to add playlists to a playlist folder

Hi

I have searched but can’t find an answer to this, only posts with references saying it can be done. I have created some smart playlists, and now I have created a playlist folder to put them in. How do I move them to this folder?

Edit - Found it. I saw the tutorials on YouTube had been updated so found the answer, drag and drop in the playlist navigator. It gets a bit tricky though if you have a lot of playlists like me as if the target you are dragging to is not visible the list does not scroll as you drag past the edge of the list as it does in other windows like say windows file exporer.