Beam / post braces
The beam/post braces are fixed to the top of the posts and to the underside of the head beam.
Two per post, so a total of sixteen is required.
The beam/post braces are decorative rather than structural, as the posts concreted into the ground are support enough for any sideways movement. For these beam/post braces you will need 16 lengths of 4x4 sawn treated pieces of lumber at approximately 16" long. (It's up to you whether you replace these beam and post braces with something more fancy.)
At the end of one of the pieces of lumber cut a 45 degree angle (fig 5). Measure back 14" from the long point of the cut and pencil mark another 45 degree angle inward. Set your circular saw blade at 22.5 deg. and cut along that pencil mark.
Repeat this on all 16 pieces of lumber.
Fix all 16 pieces in place as per fig 5 with 4" galvanized nails.
It is sometimes wise to drill the nail holes first with a slightly smaller drill bit to ensure no splitting of the lumber occurs.
Making the hub
The hub is the piece of lumber that goes to the very top of the gazebo roof (apex).
The eight roof rafters are fixed to the hub.
Get a length of 4x4 sawn treated lumber 2ft long.
Make a pencil line down the length of the lumber 1 1/4" in from the edge as per fig 6. Do the same along all four edges.
Set the angle on the circular saw to 45 degrees and rip-cut down the four pencil lines.
You now have made the hub.