first lesson template draft based on RD and RB comments

Co-authored-by @bast 
Co-authored-by @rkdarst

content/lesson-template.md

@@ -11,8 +11,43 @@
 - Exercises: ? min
 :::
 
+## [Sphinx](https://www.sphinx-doc.org)
+
+- We build all our lesson material with Sphinx
+- Generate HTML/PDF/LaTeX from RST and Markdown.
+- Many Python projects use Sphinx for documentation but **Sphinx is not limited to Python**.
+- [Read the docs](https://readthedocs.org) hosts public Sphinx documentation for free!
+- Also hostable anywhere else, like Github pages, like our lesson material
+- For code a selling point for Sphinx is that also API documentation is possible.
+
+Sphinx is a doc generator, not HTML generator. It can:
+
+- Markdown, Jupyter, and ReST (and more...) inputs. (jupyter-book is Sphinx, so anything it can do we can do. This was one of the inspirations for using Sphinx)
+- Good support for inline code. Much more than static code display, if you want to look at extensions.
+- generate different output formats (pdf, epub, etc)
+- strong cross-referencing within and between projects
+
+## [CodeRefinery lesson template](https://github.com/coderefinery/sphinx-lesson-template)
+
+It is "just Sphinx" - with extensions:
+ - The addition is various directives (boxes) tuned to lesson purposes
+ - In addition it provides a sample organization and template repo you can use so that lessons look consistent
+ - Tabs: they are very important for us and allow us to customize in-place instead of copying everything and fragmenting lessons
+ - Emphasize lines: they make it easier to spot what has changed in longer code snippets
+ - You can write Markdown (I know it's an extension and a flavor of ...) and we really like and use MyST parser
+ - It's fine if you use some other static site generator or git-based lesson method.
+
+:::{exercise}
+Find the lesson template on Github, create your own repository in your own namespace using the template and play around with the features:
+- How can you do tabs?
+- How can you highlight lines in code boxes?
+- How can you change color, logo and fonts?
+- What directives are available?
+
+> Some solution here
+:::
+
 
-Here the episode sections and text ...
 
 
 :::{keypoints}