how does it work section README

README.md

@@ -35,4 +35,12 @@ This repo is **experimental** and meant to demonstrate how the notebook could be
     Then run with the default URL set to the notebook tree:
     ```
     jupyter server --default_url="/tree"
-    ```
+    ```
+
+## How does it work?
+
+Here's a short list of what's happening" 
+* All handlers inherit from the `JupyterExtensionHandler` (i.e. [see here](https://github.com/Zsailer/notebook_server_extension/blob/master/notebook/base/handlers.py))
+* `NotebookApp` inherits from `JupyterExtensionApp`. 
+* `load_jupyter_server_extension` loads config and appends handlers to jupyter server.
+