The documentation for the ACA-Py demos is published on the aca-py.org documentation site in the Demos tab. Jump over there to learn more about using ACA-Py and going through the many demos available.
Within the ACA-Py repo itself, the source documents for the demos on aca-py.org have been moved to the docs/demo folder, starting with docs/demo/README. Edits and additions to those documents are welcome!