provide install notes and screenshot in README.

A basic update of the boiler-plate text I originally used when I
created the repository. The README now provided information on
creating a virtual environment, installing dependencies and a link to
RTR-Docs (for further information on the project).

README.md

@@ -1,7 +1,39 @@
-# light-wave
+# Light Wave
 
-An, at time of writing, python-based proof-of-concept for displaying the light reading data created with the Light Meters running the (Light Meter)[https://git.abbether.net/return-to-ritherdon/light-meter] repository.
+This is a support project to help test and monitor the [Light
+Meter](https://git.abbether.net/return-to-ritherdon/light-meter) in
+the factory (Ritherdon). It provide about a minutes worth of streamed
+light readings from the facory and displays both readings as animated
+line graph.
 
-Using this link as a starting point:
+![Screenshot of Light Wave running](screenshot.png)
 
-https://www.digikey.jp/en/maker/projects/graph-sensor-data-with-python-and-matplotlib/93f919fd4e134c48bc5cd2bc0e5a5ba2
+## Environment Setup
+
+```bash
+# Virtual environment
+python3 -m venv venv
+source venv/bin/activate
+
+# Install dependencies (with pip)
+pip install -r requirements.txt
+
+# Run the program
+python light-wave.py
+```
+**You might need to add additional packages (via `apt`)**. The most
+notable reason why is because Matplotlib needs some extra things to
+run. It looks like the list depends on what you've already installed
+on your system -- I've only checked Debian. Use the following link for
+more information about installing stuff more Matplotlib:
+
+- [Matplotlib Install
+  Notes](https://matplotlib.org/stable/users/installing.html)
+  
+## Use RTR-Docs for more Information
+
+Because this project is one of many within a bigger project. All the
+documentation has been moved to a centralised repository. All
+additional information about this project can be found at:
+
+- [RTR-Docs Repository](https://git.abbether.net/return-to-ritherdon/rtr-docs)