They were off - Tradução em português
Huddled together in the chill January wind, the players listened as a PPE fresher in a black cape read the rules of the game: a Quaffle through a hoop would score 10 points, capturing the Snitch would yield a bountiful 30, and under no circumstances was there to be any "grabbing of broomsticks". With that, they were off: two teams, with seven players each, racing round a playing field and trying to shoot a basketball through hula-hoops.
They were off. = In the context of the paragraph, "they began their competition, they began the game, they started."