How do you get Harry's broom on Lego Harry Potter 1-4?

In LEGO Harry Potter: Years 1-4, you can get Harry's broom by completing the "Quidditch" level. After the cutscene where Harry gets the broom, you'll be able to control it and use it to complete various tasks in the level. To unlock the broom for free play, you need to complete the level and collect the necessary collectibles, such as the character tokens and hidden items. Once you've done this, you can access the broom during free play mode.