Start with your first deployment, decide what to take, then put extracted loot to work in your FOB.
For your first run, choose one DMZ Order, take gear you can replace, and head for extraction when the job is done.
Short on supplies? Equip Free Loadout in the Ready Up menu. Successfully extract, and you keep the equipment you brought out.
Constantly clearing your Stash? Check storage upgrades. Missing an item for your next run? Check its recipe, then track the requirements in the 3D Printer.