Finding Aids/Collection Guides contain descriptive information about collections. They will either provide an overview of the contents of each box or a list of folder titles.
Start by reviewing the scope and content note and biographical information. They wll help you determine if the collection contains relevant information.
Folder titles can be general so it is important to review the scope and content notes at the series level if they exist.
Although you can search within most online versions of finding aids, browsing is highly recommended so you don't miss anything.
Here are the key components of a finding aid:
Biography - basic information about the creator(s) of the collection
Scope and Content - a summary of what is included in the collection
Related collections - other collections that might be of interest
Physical Description/Extent - how big it is
The Online Archive of California (OAC) provides free public access to detailed descriptions of primary resource collections maintained by more than 200 contributing institutions including libraries, special collections, archives, historical societies, and museums throughout California and collections maintained by the 10 University of California (UC) campuses.