I’ve checked column fields such as Headline, Subject, Description, Keywords, etc., but I have no idea how to enter data into them?
Advice?
The column fields that appear in the configuration pick list below the thin grey line are display-only for the document list. They are metadata fields that may or may not apply to a given document, depending on the document specs created by the author of whichever app created the document. A few of the metadata fields are editable in the Tools > Show Properties panel. Others, such as Headline are not. (Headline, for example, is - usually - an IPTC field that occurs in image files. You would need an IPTC editor, such as Adobe Bridge, to modify that field.)