Richy,
I understand that part, thanks

. But after that, where do the side pieces attach, by that I mean, when everything is assembled, should the "real cab" part hang over the bottom supports?
Side view
front -> | | < back of cab
| |
Bottom -> ----------------------------
| | <= supports?
-------------------------
Do you see what I am asking? From the plans I gather that the overhang between the cab and the supports/baseplates is 6.5"'s , seems like alot dont it?