== Edit Mode ==
Right now you're in what's known as '''Object Mode'''. In ''Object Mode'' you can move the cube around the 3D environment in relation to other objects. With the cube selected, hit '''TAB'''. This puts you in what's known as '''Edit
In ''Edit Mode'', you can change the shape and size of the cube. You could turn the cube into a puppy… or at least some day you'll be able to.