Argos reserving items?

There's an item I reserved at argos (UK), but it said it had to be ordered into the store and would be available to collect 3 days later. I've been given a reservation number but I'm not sure whether I was supposed to go in and give them the reservation number first so they can order it into the store or whether it's already been ordered into the store and I just turn up in 3 days with the reservation number?