There is no 'part' to know, if dancing at anything beyond a novice level. When I dance, I choose the figures to lead based on the music, my mood, my partner and the available space on the floor. I have not much idea what I will lead in four bar's time, and my partner has no idea at all. If I can't lead the figure, she can't follow: but no one would be able to see what is going on, because the signals are far too subtle, and are felt, not seen. If this was a burden to me, and a chore for my partner, neither of us would bother. You should try dancing, sometime.
I've no interest in dancing sequences.