Denis Villenueve's "Dune" is premiering in a few short days. Those already familiar with the eponymous book by Frank Herbert are eagerly awaiting to see Villeneuve's on-screen adaptation.Those who know nothing about Frank Herbert's "Dune," however, might be a bit overwhelmed by all the characters in the story. This article is for those people (or for "Dune" readers who want a refresher).