Mark the locations for corner posts for your gazebo with stakes. Square the outline by measuring corner to corner with a tape measure and adjusting stakes until those measurements are identical. Dig holes at the corners with a post hole digger 12 to 18 inches deep.
Set bamboo poles 6 inches in diameter in the holes; plumb them, ensuring they are level, and secure them with concrete poured in the holes slightly above ground level. Make poles 8 feet high on one side, 9 feet on the other, for a single slope roof, or set poles the same height for a pitched roof.
Make two bamboo frames, one for a floor and one for a roof. Use poles about 4 inches in diameter, two to fit between the upright poles and two to overlap these at the ends. Fasten the poles at the corners with nails and a hammer and tie them with waxed lashing cord. Fasten the bottom floor frame to the outsides of the poles about a foot off the ground. Brace the corners with concrete blocks underneath.
Fasten 4-inch diameter joists between two sides of the floor frame at 24-inch intervals. Cover the floor with smaller canes, about 2 inches in diameter, placed tightly together and nailed to the joists and outer frame. As an alternative, cover the floor with bamboo flooring strips, cut to form a more even floor. Nail these in place.
Put the roof frame around the tops of the poles, using the difference in height to provide a roof slope. Secure it with nails and waxing cord. Add rafter poles across the slope of the roof, with bamboo about 2 inches in diameter, nailed and corded to the frame at 24-inch intervals. Frame a pitched roof with canes cut like rafters, one in the center of each wall to a peak and one from each corner to the center peak. Fasten these to a 6-inch cane at the center peak to hold the elements together.
Make a roof covering of small bamboo canes lashed together with waxed cord. Lay it on the rafters and fasten it with nails and cord. Form this into a sheet on the ground, then put it on the roof and fasten it with nails and cord to the rafters.