I don't really see the point of laughing, we all started out somewhere as novices.
The version of the file you have is normally built with cardstock, strengthened with fiberglass, and sanded/detailed/finished up in the same manner that all the other projects on this site are normally done.
For the scale you are trying to attempt(18"x18"x18"), going that route might be counterproductive, as well as take a lot of time. Instead of building it out of paper, print the pieces out, cut them out and trace them to a harder material, such as cardboard.
Using th other files(the ones with the box) might help out a little more, since they give a better visual for the size you want to make it.
As always, a bit of trial and error always helps in the long run......you might want to try it on a smaller scale so you know how to proceed first.
I am using the ALLSOLID version to do a smaller cube (small enough to sit on a desk), but the route I plan on building it includes filling the inside with smoothcast, to give it a decent weight.
Are you planning on making it the same way bevbor did, or are you trying something different (i.e. making it hollow and using it to store items inside)?