Simply put, here's how I assembled my box blade.
Attach the large supports inside the vertical rails with the bolt heads on the outside and the nuts on the inside. Attach the small supports inside that same rail with the bolts the same way. Attach the other, upper end inside the large support with the bolts facing the same way. Turn your tines around and you're good to go.
I hope this explains it well. It's really a piece of cake to do. My only concern after I'd done it was whether or not I'd put the supports on the proper side of the rail and, fortunately, I had. It just seemed like the natural way to go but, of course, then I got to thinking about it and wondering so I asked. Jim, as always, was most helpful. Good luck with your new toys. I hope you like yours as well as I do mine. /w3tcompact/icons/smile.gif