>>211712020i've never worked fast food exactly, though i've worked in a few kitchens
I imagine fast food is the same just scaled to be simpler and higher quantity, but the same fundamentals are there. Pretty much every kitchen has a line and underneath that line are prepped back up containers of cut veggies that you swap out when a container usually a 1/3 or 1/9 pan runs out
Most of the "cooking" is just grabbing handfuls out of these containers and throwing them ontop of something. It's not rocket science