I just watched Bill Cogswell's "fundamental submission chains" seminar DVD and would like to comment on it. This seminar is on 2 DVD's that are an hour long each. It is full of submission chains that everyone who grapples must know. However it is not just "the basics", as some of the techniques will definitely not be known by everyone.
There are about a dozen or so series of techniques from many positions, each comprised of several submissions each that flow right into each other. Bill offers several options from many positions to continue transition to more submissions regardless of how your opponent defends. I would recommend this DVD for all skill levels, as it is easy to follow and offers great material. The submissions on this DVD are all what I call "high percentage" in that they work on someone about your own skill level a high percentage of the time. It really is material that every grappler needs to know. There are no chapters on the DVD, but I just used the fast-forward and rewind buttons when necessary and had no problems.