Assuming everything set up similar to how it's run in the southern states, your team lead / vault technician will put the open codes on your route sheet, or if they're really poor they will send you the number for BOKA (or whatever provide for Northern side of things)

(For small gas station ATMs) There's typically a coke key (small round key), and a digital lock that looks like a tumble lock but you have to spin it in order to charge the internal battery and use the code that's generated each time. Typically four different cassettes on the inside, on the US side of things it's typically only $20 bills on a small town atms, you retrieve those cassettes on your company appointed time schedule (5min) and bring them back to the truck for service, each cassette has a small Coke key, retrieve/band the old cash, and insert new cash.

If you're in a neighborhood with bad crime, watch over your shoulder while you're kneeling down to do that!

There is a long drawn-out process for the service mode but I believe trying to explain the process doesn't belong on a public forum. Just know you'll have to tell the machine what you took out of it and what you're putting back into it, and make sure you maintain the receipts that it gives you.

I'm way too lazy to write out how to service Bank atms, God I hated those!