First let me say that there is no "correct" version of a movie, unless you have been asked to find a particular one among many that may have been shot.
In this case, it would seem that there is only one movie you can watch. It is Oliver Parker's version (1995) with Lawrence Fishburne starring as Othello. Other versions -Orson Welles' (1952) and Laurence Olivier's (1965) cannot be downloaded, although scenes of both are found in YouTube.
You can watch it free online at www.ovguide.com/othello-9202a8c04000641f8000000000d64966t
When looking for a movie, you need to write the name followed by the word "movie" and click on "search." All the available versions will appear on your screen.
Enjoy the movie. It is indeed remarkable.