I started with a foamcore base with walls and flooring, glued together using scholastic glue. I then added the walkway on stilts, ledges for the loading bays and the raised flooring, binding with the same glue. The wall pattern (inside and outside) came after as did the floor pattern, which in hindsight should have come after (you live and learn). The patterns themselves came from the internet (thanks google!),and they were glued to the walls using Super77 spray glue. The accessory bits were next; the Pegasus ramp and ramp support, glued into the foamcore for extra support and angled in such a way that a standard model will not fall or slide down; the Pegasus bannisters, pinned through at two points and anchored into the walkway; the ladder, anchored into the flooring and propped up against the walkway; and finally, the two step Pegasus staircase on the outside, which was anchored into the wall. And voila an industrial warehouse with three shipping bays.
Here are more images of the final product: