I dug holes 28″ deep through soil and clay, then positioned concrete cylinders. Sequentially I then tapped each 3 foot long 3/4″-10 threaded dowel into the bottom of the hole surface in relation to each corresponding hole on the hinge plate. Once all threaded dowels were established, I poured quickcrete into each cylinder to the brim. I joined all four of the inner exposed concrete forms by digging a pit in the center and filling it too with concrete. After the concrete solidified, I mounted the hinge plate on the foundation. I actually screwed on some 3/4″ nuts n each threaded dowel so that I could manually adjust the height of each corner should there be any mistake (inevitably there was). I placed the bottom tower section on the hinge plate and secured it with provided screws on the hinge brackets.