Go to the Toy Box Hub. Talk to the character that creates the area with the Disney castle in the background. Go toward the castle, and the second-to-last person you can talk to on your right will unlock the theater. Go in, and talk to the usher. He will unlock a few posters you can select to load toy boxes. Click either and hit play. The achievement will unlock once the selected toy box loads. You can play it or quit immediately after.