Shelf filling process at a supermarket?

This is the basic principle. Most supermarkets re-stock when the shelf stock level drops to two thirds full. You will be told which aisles to work by your supervisor or team leader. You need to check best before dates and put the earlier dates at the front of the shelf so that they get picked first. You will probably be given a trolley with a whole aisle's worth of goods to stack and then when you have finished your supervisor or team leader will move you to another part of the store.