Help with enums

Hi,

I don't have much proficiency with RDF. I have a project that includes a
schema.rdfa file holding my external extensions. I would like to specify
the enumeration values for a Schema.org property. For example,
https://schema.org/videoFrameSize is a property defined as "The frame size
of the video", with an expected type of text. I am using enumerated values
that correspond to well-known frame sizes with a label like
"WideLandscapeHd".

Should I do anything to show what my enumerations are in my external
extension file? How would anyone know what the definitions are if I don't
(granting that I understand existing tooling might not understand them)?

Thanks!