It is not possible to browse the shelves as in a library. When you have selected the archives you want to see, they will be fetched for you from the repository. Some archives may be unavailable for research, for reasons of confidentiality, or because they are being repaired. There is no general and unrestricted right of public access to archives. Access rules are usually set by law or the person or organisation that originally accumulated the documents.
Subject enquiries become provenance enquiries.
The arrangement of archives according to 'provenance' and 'original order' means that subject enquiries have to be reoriented if the archives are to yield evidence. You will need to work out which person or organisation would have had an interest in or functional responsibility for your subject area, and what records they might therefore have created about it. Archivists find this is one of the hardest things about archives for researchers to remember so here are a couple of real-life examples from one Archives. Archivists at Sydney City Council are often asked to help people find out when their old terrace houses were built. There were no documents specifically accumulated on this subject, because it was of no official interest to the Council.