Although finding aids at different libraries may look different or use slightly different terminology, they will tend to contain similar sections:
The first section in the finding aid will provide a general overview. Here you will usually find the title, the creator, the dates covered, and the size of the collection. Like books, all archival collections should have a unique number or call number -- in this example "Coll044" for Collection 44 -- that you can use to reference or request the collection.
There may be a section that provides historical context about the person, organization, or movement covered in the collection. This may be in a timeline or narrative paragraph format, and can also contain information outside of the breadth of the collection. This section is typically written by the archivist or processing staff, not by the person or organization themselves.
The Scope and Content section includes more information about navigating the collection. Archival collections are arranged into series, and sometimes sub-series, which are groupings of related documents within the collection. In personal papers, you may find a series for the person's correspondence, one for diaries, one for photographs, etc. In organizational papers the series may reflect different officers or departments (creators) or types of documents like annual reports, financial files, awards, etc. Looking carefully at this section will help you to determine if the information that you're looking for is in the collection and where you should decide to start looking.
Provenance means the source of an item. Archives and museums use provenance to show the authenticity of the item or collection. This section shows the provenance, usually by stating the donor of the collection, and also discusses any actions that the archives took when processing the collection. This could include removing materials, preservation actions, or imposing an arrangement on the collection.
In some cases there may be access restrictions placed on a collection at the behest of the donor or creator. This section will also state any usage restrictions, for example who owns the intellectual property rights for the materials. This may not impact your access to the collection but it could mean an extra step if you want to publish materials in a thesis or book.
If subjects are listed, you can use these to search other library catalogs to find related materials. The examples shown here are Library of Congress Subject Headings; please note that controlled vocabularies often reflect the biases of the people and systems that create them, so terms for underrepresented communities and people of color may not always use terminology preferred by those groups.
Finally, a finding aid may or may not include a listing of the materials included in the collection. Collections are often described hierarchically, so there may be a "collection level" description (see the Overview or Scope & Content sections), "series level" descriptions, or titles for boxes or folders of materials. Rarely will there be an item level list unless the collection has been digitized. A container list will help you to decide which boxes to request when you visit a Special Collections or archives to work directly with materials.