You will need wood glue, a brad nailer or a drill and wood screws, clamps, a face mask, and some muscle. If you don’t have a brad nailer you could hand nail as well. We suggest #8 wood screw at least 2 1/4″ long.
If you don't have clamps or a brad nailer, you can use ratchet straps or even masking tape to hole the pieces in place while the glue dries.