Who's strategy does Ender study in the film?
While he is the commander of Dragon army, Ender is challenged more and more by every battle, but because he continues to win, he is running out of mentors and teachers who can continue to teach him new things and to come up with new ideas.
He decides to return to the video room in Chapter 11, to watch the propaganda videos of the first invasion. While much of the videos have been edited to show the heroism of Mazer Rackham and little else, Ender starts to study the strategy of the Buggers in the film. He learns that they seem to move as a unit, without any lag time, and seemingly with instantaneous communication.
He also notices that they seem to follow one apparent strategy (whether it will work or not) and that is to "gather the greatest number of ships at the key point of conflict" (188). He assumes that discipline is very tight and that the buggers take subordination very seriously.