how to add bookmarks folder back into bookmarks in safari?

I used the old techique of dragging a folder of bookmarks to the desktop for quick alphabetical sorting. However there seems to be no way to drag the organized folder back into the browser bookmarks. This folder has several folders withing folders - an extensive collection of things needed. Organizing it inside safari is a nuisance. Is this means of working with bookmarks no longer possible in the latest Sierra version of the OS?