This is a grocery shop from the time when you were actually served instead of having to do all the work yourself and still having to pay for the privilege as happens now. Most of the items for sale were kept on shelves behind the counter and you went up to the counter where an assistant would ask you what you wanted and fetch it from the shelf, placing it on the counter and when you had all you required the assistant would pack it up for you.
Shops of this sort sold a huge range of items including some ironmongery for instance, although milk and bread would mostly be delivered house to house by the dairy and bakery. Milk was carted around in churns and measured with long handled scoops into ones own receptacle, so there was no container cost.
The larger shops had quite a few assistants, poorly paid as most menial jobs were and still are. Such is progress that with all the advancement of science and technology large companies seem to have thrived whilst the poorer paid employees haven’t.