Hover you mouse over the folder that you would like to delete and click the “more options” gear. Then select “Delete”. This will move the folder into the trash area. Keep in mind anything contained within this folder will now be in the trash as well.
To permanently delete the folder, click the “trash” button. Then click the folder you wish to permanently delete and chose the “delete” option. Once you have deleted an item from the “trash”, it is now permanently deleted, and you may not recover it ever again.