Add Dask Extension instructions

README.md

@@ -106,6 +106,26 @@ If your workload exceeds your server size, your server may be allowed to use add
 
 Under Construction: In Jupyter, kernels are the background processes that execute cells and return results for display. To select the kernel on which you want to run your Notebook, go to the Kernel menu and choose Change Kernel. You can also click directly on the name of the active kernel to switch to another one. The bottom of the JupyterLab window lists the github branch as well as the name of the kernel in use. The kernel is listed as either 'idle' or 'busy', which is useful to know if your kernel is working or has crashed.
 
+### What is the Dask extension and how do I use it?
+
+[Dask](https://www.dask.org/) is a python library for parallel computing, roughly similar to the `multiprocessing` standard library.
+The Fornax Science Console includes the [Dask JupyterLab Extension](https://github.com/dask/dask-labextension) which can be used to manage a Dask cluster and monitor the progress of submitted functions, all from within JupyterLab.
+The charts that make up Dask's monitoring dashboard are embedded directly in JupyterLab panes which can be moved around into custom arrangements.
+Here are some chart examples:
+
+![ ](./static/images/dask_chart_examples.png)
+
+Quick-start instructions:
+
+- On the left-hand side of the Console, click the Dask icon that looks like this: ![ ](./static/images/dask_extension_button.png)
+- Scroll down and click "+NEW" next to "CLUSTERS" to start a new cluster.
+- Right above that, once the cluster starts, you'll see a column of yellow buttons appear with the names of available charts.
+  Click on any of them and a new tab will open showing the selected chart.
+  You can drag and drop the tab to move it somewhere else on the screen.
+  In the screenshot above, several charts are open and arranged next to each other.
+- Start or restart the kernel for the notebook you're working in so that it will recognize the cluster.
+- Submit functions to Dask as normal ([Dask Quickstart](https://distributed.dask.org/en/latest/quickstart.html)) and you will see the charts update as the work progresses.
+
 ### Does work persist between sessions?
   * Files in your home directory will persist between sessions.
   * pip installs will persist across kernel restarts, but not across logging out and back in.