In Keynotes: select a Keynote or folder.
Enter or edit its data in the Selected Keynote section.

Keynote data
Keynote data include Key, Title, Description, and Reference.
The Key is mandatory and unique; the others are optional.
The Reference usually refers to an external database, e.g. a number or web link.
Folder data
Folder data include Key, Title, and Reference.
A Key or Title is mandatory; the others are optional.