You are wasting your time. It is impossible to make anything foolproof, because fools are so damned ingenious.
I recently bought a cheap vacuum cleaner. Turned out the price was low because (a) there was some assembly required (I should have figured this out from the size and shape of the box) and (b) there were no instructions. In any language.
On the whole it didn't take any longer having to figure it out for myself. Well, apart from the two leftover screws. I'll never know if these were spares-- somehow I doubt this-- or if I missed a couple of vital reinforcement points. If it ever falls apart, I'll look for little holes.