update readme for more public viewing and interaction

Author: gregsdennis

README.md

@@ -1,4 +1,19 @@
-This repo controls the _Learn `json-everything`_ website and all of its content.
+## Welcome
 
-- Main site (playground): https://json-everything.net
-- Learning sandbox: https://learn.json-everything.net
+This repository houses the source for `json-everything` learning site, https://learn.json-everything.net.
+
+## Contributing
+
+We're happy to accept and review proposals for lessons.  In general, lessons will cover how to use the libraries.
+
+Each lesson should focus on a single feature of the library.  The coding exercise should be tailored so that completion requires the learner to use the feature.
+
+There is a lesson editor WPF app that makes creating lessons quite simple.  If you're just creating a lesson, running this app (`run edit`) is recommended.
+
+The main project's [CODE OF CONDUCT](https://github.com/json-everything/json-everything/blob/master/CODE_OF_CONDUCT.md) also applies.
+
+## Running locally
+
+The site is a Blazor WASM app running .Net 8, and it's published via GitHub Pages.
+
+You can run the `run.cmd` script to start up the site.  If you add an `edit` parameter, it'll run the editor.