publishing: no default publishing function, or symbol is not defined

["Christopher W. Ryan" via "General discussions about Org-mode." <emacs-orgmode@gnu.org>]

I'm making my first foray into publishing a project. I'm running GNU
Emacs 26.2 (build 1, x86_64-w64-mingw32) of 2019-04-13, on Windows 10.

I've defined a single project, just to try it out and learn.  Here is
the relevant portion of my .emacs file


;; Projects and publishing
;;
(setq org-publish-project-alist
      '(("CaseInvestigationTrainingAndReferenceManual"
         :base-directory
"E:/DATA/BCHD/CD/ChinaCoronavirus2019/CommCare/Sandbox/"
         :publishing-directory
"E:/DATA/BCHD/CD/ChinaCoronavirus2019/CommCare/Sandbox/StagingArea")))


There is one org file in ......../Sandbox,  called
WorkAreaForIndexingTrainingAndReferenceManual-7-June.org

(as the filename suggests, I'm mostly interested in learning how to make
an index).

If I execute C-c C-e P a  whilie in the org file I am trying to publish,
I get an error message that there is "No publishing function chosen".  I
thought org-publish-org-to-html was the default, as described here:

https://www.gnu.org/software/emacs/manual/html_node/org/Publishing-action.html

But if I modify the relevant section of my .emacs file like this,
specifying a publishing action:

;; Projects and publishing
;;
(setq org-publish-project-alist
      '(("CaseInvestigationTrainingAndReferenceManual"
         :base-directory
"E:/DATA/BCHD/CD/ChinaCoronavirus2019/CommCare/Sandbox/"
         :publishing-directory
"E:/DATA/BCHD/CD/ChinaCoronavirus2019/CommCare/Sandbox/StagingArea"
         :publishing-function org-publish-org-to-html)))

and try again, I get an error message that I can't figure out: "Symbol’s
function definition is void: org-publish-org-to-html"

Grateful for any guidance.

Thanks.

--Chris Ryan