I would guess there were about 40 people, mostly beginners, at the seminar. They were students at the IMB classes who were invited to the BJJ class for a special 2 hour Jiu-jitsu introduction. For most of them it was their first real introduction to BJJ, though there were some who had a bit of experience.
Here was the format I used:
Demonstrated each of the major positions in BJJ and the benefits and drawbacks of each
Then I taught the following:
the double leg (standing) against the punch
knee on the belly to armlock
them how to mount from knee on the belly
americana from mount
taking the back from the mount with rnc finish
guard defense against punches
kimura from guard
guillotine from guard
kimura to guillotine combination
then we sparred.
I rolled with a few guys and let one of the guys start on my back and get the rnc like we practiced (after tapping him a couple of times). The funny part was hearing the people watching say, "oooh, he got him!"