Hutches are usually built out of plywood and wire, and propped up off the ground by planks of wood. A typical rabbit hutch is relatively easy to build, offering your rabbit sturdy and reliable shelter, good ventilation and nest boxes where bunnies can be born.
Take your 2 by 4s and use them to construct a support frame around the wire cage you procured in Step 2. This will make your rabbit hutch sturdier and more better suited for use outdoors or in a barn.
Finish by building a plywood roof for the hutch. While some people simply prefer to lay a loose piece of plywood over the top, a hinged roof is much better. It is also wiser to build the roof on a slope to prevent precipitation from collecting on top of it.