In the first area after the opening set of scenes (once you've gotten the fez) you'll need to collect all the cube pieces, both outside the rooms and inside a few of the rooms, you'll finally form the cube (after 8 pieces). This will cause the cube to form over your head and you to earn your first cube as well as this trophy.
You can skip doing this by getting an anti-cube, but eventually you will get a 8 pieces of a cube, and unlock this.