As the Controller you set the stage, speak for every character but the hero, and answer each move. This is your toolbox.
Read what the hero did, then answer: move someone, change the room, give a character a line, narrate what happens. When the stage looks right, send the beat, and the turn passes to your Player.
Want something to play out over several beats? Send it as a Cutscene: the beat goes out and you keep the turn.
Cues let you prepare a beat ahead, off the clock. Only you see them, they stay on this device, and you can use one on your turn.
Run the world: a practice scene