Some documentation

README.md

@@ -1,5 +1,5 @@
 # unbound-manual
-The Official Unbound User Manual, published at [unbound.docs.nlnetlabs.nl](https://unbound.docs.nlnetlabs.nl/)
+The Official Unbound User Manual, published at [unbound.docs.nlnetlabs.nl](https://unbound.docs.nlnetlabs.nl/).
 
 
 ## Style Guide
@@ -9,3 +9,52 @@ English style, we use the [European Commission’s English Style Guide] as
 guidance.
 
 [European Commission’s English Style Guide]: https://ec.europa.eu/info/sites/info/files/styleguide_english_dgt_en.pdf
+
+
+## Building locally
+
+The documentation here relies on [Sphinx](https://www.sphinx-doc.org) which is
+a documentation generator written in Python.
+
+You would need the packages/versions listed in [requirements.txt](requirements.txt) either in your system or in your Python environment (recommended) like:
+```
+pip install -r requirements.txt
+```
+
+
+## The Unbound submodule
+
+This repository has the Unbound source repository as a submodule.
+This is mainly done in order for the manpages to live authoritatively next to
+the code they are documenting.
+
+### Working with the submodule
+
+When first cloning this repository you would need to additionally do:
+```
+git submodule update --init
+
+```
+and everytime after you pull new changes.
+
+Or break out of your muscle memory and use:
+```
+git clone --recurse-submodules ...
+```
+when first cloning this repository, and:
+```
+git pull --recurse-submodules
+```
+when pulling in changes.
+
+### Generating updated manpages
+
+When the manpages of the Unbound source are updated, this repository's Unbound
+submodule needs to point to the new version.
+Checkout the relevant tag/branch/commit and commit the change.
+
+The manpages can then be generated by running:
+```
+make man
+```
+The manpages will be generated in `build/man`.