You find an archive description that lists photographs, catalogues and technical papers. It feels like discovering the answer. More accurately, you have found a route towards possible evidence. A finding aid tells you how a collection is described and organised; it does not mean you have inspected every item.
Read the hierarchy
Look for the collection title and identifier, then the series and folder descriptions beneath them. Keep those levels separate in your notes. A date range for the whole collection is not necessarily the date of one document.
The DuPont Nylon Collection finding aid at the Smithsonian lists series for production records and publications, among other material. That structure helps a researcher choose where to look, while individual documents still require examination.
Write one request-sized question
Instead of “I want the history of nylon”, ask which listed folder might contain a dated catalogue or a photograph relevant to your question. Note the identifier and wording of the description so an archivist can recognise what you mean.
Check access and reproduction conditions before planning a visit or requesting copies. A public description does not guarantee that every item is digitised or immediately available online.
Label your research status accurately
Use separate notes for “listed in finding aid”, “digital image inspected” and “document read”. This prevents an attractive collection summary from being cited as though it contained a specific passage you have never seen.
If the relevant material is not accessible, you can still report the useful lead and the limitation. Do not fill the missing document with assumptions from a general history.
For a next step, compare how to read an advertisement with following a documentary trail. The finding aid gets you to a source; the reading begins when you examine what that source actually contains.