How do I learn how the whole store actually runs?

You do your own tasks well, but the bigger picture, how the whole store fits together and keeps running, still feels beyond you. That is not a sign you are not capable. It is a sign you have only ever been shown your own piece. No one is born understanding the whole; they learn it by looking up from their corner and asking how it all connects. The store is really just a set of connected jobs, each one handing off to the next: deliveries become stock, stock becomes displays, displays become sales, sales become the numbers that decide the next order. Once you start seeing those handoffs, the mystery shrinks. It is less complicated than it looks from inside one role. It is just a chain, and you already know one link of it well. So become curious on purpose. Ask the people in other roles what their day involves and how it connects to yours. Watch what happens before your task and after it. Volunteer for something outside your usual lane. Understanding the whole comes not from a manual but from steady curiosity about the links around you. Pull on one at a time, and the picture fills in.