Update building the docs instructions

docs/README.md

@@ -1,9 +1,31 @@
 # Auspice 'Read The Docs' Documentation.
 
-Very much a work-in-progress!
 
-```
-make clean
-make html
-open _build/html/index.html
-```
+## Building the docs
+
+Build dependencies are managed with [Conda](https://conda.io).
+Install them
+into an isolated environment named `auspice-docs` with:
+
+    conda env create
+
+Enter the environment with:
+
+    conda activate auspice-docs
+
+You can now build the documentation with:
+
+    make html
+
+which invokes Sphinx to build static HTML pages in `build/html/`.
+You can view them by running:
+
+    open build/html/index.html
+
+You can clean the build directory for a fresh start with:
+
+    make clean
+
+Leave the environment with:
+
+    conda deactivate