It is several shops, including Olivanders, where you can buy your own wand and see all the wands from the movies. There are window displays with brooms and books. There are also stores with school uniforms (for Halloween if you like) and a movie set with lego sets, directors chairs and props from the movies.
If you can't make it to the store, below are a few photos to let you know what it's like. If you are abroad and would like to see more photos, do let me know and I can head back and take some more: