Assembly of the stairs was not difficult, and once assembled, the stairs were reasonably sturdy in the water. Given the absence of any lock washers, I added stainless steel lock nuts to all the bolt ends.
The plan to attach the stairs to the dock was essentially impractical in my situation. This plan called for overlapping approximately a one-inch angle iron (aluminum) over the edge of the dock, then screw this in with two one inch #6 screws. In my situation in a bay of Lake Ontario this would last about 15 minutes. I improvised by bolting a 2" x 4" to the width of the top of the stairs, attached deck frame holders to the dock, then inserted the 2' x 4" into the deck frame holders.
Overall, I am pleased with these stairs.