Dig two 36" deep holes 8 feet apart. Place the two 6x6 posts into the holes and fill with concrete.
Trim the 4 4-foot-long pieces of 2x6 as shown. Bolt to the top of the 6x6 posts. Using brackets, screw the 4 12-foot-long 2x6s to the "support beams" as shown. These will create the trellis for the arbor. Screw 2x2 cedar pieces along the top of the arbor about 1 inch apart.
Drill a hole into the center of the two 6x6 posts for hammock hooks. Screw in 2 large eye hooks. Your garden arbor is ready for your hammock!