From the preview:
The Engineers who serve the Rebellion come from myriad backgrounds. Research labs, academia, metropolitan speeder shops, and everything in between are fertile grounds for the practical and theoretical training required to literally and figuratively build a resistance to the rule of the Empire. Someone needs to design the equipment that someone else needs to build that someone else needs to repair that someone else needs to salvage for parts to reassemble their light freighter that got half its hull blasted off while running a blockade of Star Destroyers. At every point in the lifetime of a piece of equipment, there is an Engineer there ready to put it to good use.
In today's preview, we'll take a closer look at just how resourceful these Engineers have to be, especially when working on behalf of an underfunded rebellion that's severely lacking infrastructure. Just as much as the Rebel Alliance's success was dependent upon the courage and determination of its brave soldiers, it needed the creativity and elbow grease of its Engineers. Fully Operational, the Engineer sourcebook for Star Wars™: Age of Rebellion provides the tools you need to build a Rebellion from nothing.