Designed to be stacked vertically. Bottom floor houses all of the conveyor belts/ splitters/ etc. Max stack is 4 (output max of Mk.4 belts, as that's what I have). Vertical conveyors on the outside can send ingots to higher floors/ bring screws down. For the input/ output conveyors, from left to right is input of ingots, output of ingots (for other floors), input of screws (from other floors), output of screws.

you will have to adjust every other floor's inputs/ outputs (just rotate the splitter/ merger and rerun a couple belts)

Per Minute / Per Floor Input 30 Iron Ingot Output 120 Screws