Did Jo Rowling Have This Problem?

I hit a roadblock with my first draft of The Curse of the Blood Stone. The scene in question involved a mounted game that I "invented" for my YA fantasy novel. In actuality I have combined two existing games, one of which I was vaguely familiar with and the other I'd never heard of before.

While pondering how to approach the problem scene I returned to the Internet to watch a view videos that helped me figure out how to block out the movements of the characters.

So I dive into the scene and within a couple of paragraphs I'm struggling with the locations of the players on the field. Ack! I snatch a piece of paper and the next thing I know I'm doing the football schematic thing. You know -- the Xs and Os with the arrows going every which way. By the time I was done my sketch looked like a bowl of spaghetti -- but it worked. I think. At least I completed the action and I hope the reader can follow it.

Now -- my game is fairly conventional in that it is played on a large field (or pitch) with a goal at each end. No flying around. Strictly earthbound. And I have only three players per team participating in the action.

How in the world did Jo Rowling block out the movement of Harry et al. for a Quidditch match with everyone flying all over the place?! My thinking cap is off to her because adding the extra dimension of up-and-down to back-and-forth would have given me fits.

Anyway, I'm glad that I can move on from this scene. It is significant for my vision of the novel's climactic scene -- thus the need to get it right.