I applaud your efforts to research a topic so huge. It's like attempting to explain the Olympic games in five minutes.
BDSM is so many things to so many people....with no rules or boundaries save for those made by the people in the relationship, that I'm not sure that it's a containable topic. Perhaps easier to define BDSM as everything that is outside the box.....

It sounds overwhelming to try to explain it to anyone with any kind of time frame, hence my suggestion of choosing one aspect (which, in itself, can include ANY kinky play....so even that isn't wholly definitive).

Good luck to you.