I got the site leveled. Well, almost; the yard slopes, so nothing is ever perfectly level even when trying. But it was as close as I could get it without making terraces.
The braces were fun to make. I actually got them cut to have points fitted into the corners. Took some geometry. If the frames were squares, it would have been easy (45 degree cuts). But they are rectangles. I eventually figured out that they had to be 55 degrees cuts on one side and 35 degrees on the other (55 and 35 equals 90 degrees). My 11th grade geometry teacher would be proud of me! Who says that stuff is useless?
That's part of the fun of building stuff myself; solving problems like that. Building it for the long-term, I both glued and screwed the braces. Screwing the braces into the frames was some work, but I won't bore you with the details.
BTW, the picture below looks like there are X braces, but that is just 2 of them stacked together. Each frame has one brace. That is sufficient.
I'm used to adjustments. "Design in concept, build in reality". So I made the post holes larger in the direction of the error.
The important part was to get the first corner post and 2 frames attached level and squared in all directions. From that, all the other posts will be easier. That board on top is temporarily screwed on to hold the posts and sides in place while the clay dries.
It may rain tomorrow, so I don't know if I can do much there tomorrow. That's OK, I have other work to do. My "To Do" list is way too long...