Check this awesome classic video of the Gracies demonstrating BJJ in 1988. In this video, they explain the fundamentals of BJJ and some of the technique is explained in great detail. They break down the scoring of BJJ and explain why each position gets certain points.
Chuck brought the Gracies to teach his black belts in the UFAF. He visited the Gracies in Rio, Brazil and was impressed. He had them all fly out to Las Vegas to teach the seminar.