DOC: provide rudimentary instructions on how to build website locally

Closes #96

README.md

@@ -16,3 +16,17 @@ complete word
 *	**license** (**not** licence); in general, prefer American spelling
 *	limited use of "please"
 *	steps should start with 1, not 0
+
+## HOWTO
+
+This handbook uses [mkdocs](https://www.mkdocs.org/) to render the handbook written as a collection of markdown files into a website.
+If you would like to render it locally, you would need to create and configure a python environment according to configuration provided in [requirements.txt](./requirements.txt) file, e.g. via
+
+   python3 -m venv venv && source venv/bin/activate && python3 -m pip install -r requirements.txt
+
+And your current session would already be using that virtual Python environment, which you could deactivate by executing `deactivate` command.
+If in the future you would need to activate it, just `source venv/bin/activate` again.
+
+After that you can either 
+- do one time manual build using `mkdocs build` and find built website under `site/` folder.
+- run `mkdocs serve` which would not only build website and start a local webserver for you to visit rendered version at e.g., http://0.0.0.0:8000/, but also it would automatically re-build if you change any source markdown or configuration file.