I have an 8 x 5-ft shed.  And it is a great shed / shop.
The ONLY complaint I have was attempting to snap the corrner / wall segment tabs into the flooring slots.  That was extremely difficult if not impossible.  Simply pulling down on these segments to install corners / walls into the flooring did not work for me.
I tried two methods that helped.  The first was a heat gun to &amp;quot;soften&amp;quot; the tabs and slots. This method took some time for the tabs / slots to warm up.
The best method was to place the corner / wall segments in-place on the flooring and spray the tabs / slots with WD-40.  Bingo! ! !
Also, to strenghten the flooring, I installed cement backer-board that made the flooring substantial.  Now, no worry piercing the flooring.
Also, I would suggest purchasing the shelving vertical bars to strengthing the side walls.