How do deliveries in shopping centres work?

They deliver through the back.

In many shopping centres (not individual stores on a street) they have an area designated as a delivery zone. The lorries go there and drop their loads and the drivers/helpers push the goods in on dollies (2 wheel or 4 wheel) and go to the various shops. These guys are normally pretty quick as they have several stops on their routes and have to have them done as early as possible (normally). Many of the shops have a couple of staff in early to open up for the deliveries and perform stocking jobs of putting the new goods away or in the store room. A lot of retail store deliveries are done on 2 wheel dollies with some on convertible 2 wheel to 4 wheel units. Some go through a back door and others do unfortunately go through the front doors and yes can interfere with patrons as the delivery people manoeuvre through the store.