1 Answer

You sign in first.

When you signed in, press your icon and then go to Video Manager.

When you see Playlists, click it.

If you see a couple of lists, in the right. You will EDIT press it.

When you pressed the edit button to the one you wished for. You will see a box, a action bar and   add by url.
You will press the box and go to the action bar and you will three things. Move to top, Move to bottom and Remove videos from playlist (I haven't finished though, this the beginning! This if you want to delete the videos in your list)

If you want to permanently delete your playlist. Just like I said about going to the EDIT icon. 
In the right, there will be description, privacy, settings and DELETE PLAYLIST.

You will click that button and there your playlist is gone!

Hope that helped you and will help others who read it! :D