[docs] Improve README for newcomers.

README.md

@@ -1,8 +1,41 @@
 # cdist-contrib
 
-This project extends the [cdist](https://www.cdi.st/) configuration management
+This project extends the [cdist][cdist] configuration management
 tool with community-maitained types which are either too specific to fit/be
 maintained in cdist itself or were not accepted in code cdist but could still
 be useful.
 
 The releases of cdist-contrib are not necessarly synced with cdist itself.
+
+## Using cdist-contrib
+
+We would recommend that you clone this repository next to your regular cdist
+config directory, then setup `conf_dir` with relative paths in
+[cdist configuration][cdistconfig].
+
+An example of this would be:
+
+```ini
+# contents of cdist.cfg next to cdist-contrib
+[GLOBAL]
+# Notice that types defined in last dir win and can override native types.
+# Consider using a prefix for your own types to avoid collisions.
+conf_dir = cdist-contrib:cdist-private
+```
+
+And you would run [cdist][cdist] from the same directory as follows:
+
+    cdist config -g cdist.cfg
+    # Or setup your CDIST_CONFIG_FILE environment variable and run as usual
+
+
+## Participating in the [cdist][cdist] community
+
+Join us on [#cdist:ungleich.ch][cdistmatrix] on matrix or on
+[#cdist over mattermost][cdistmattermost].
+
+
+[cdist]: https://www.cdi.st/
+[cdistconfig]: https://www.cdi.st/manual/latest/cdist-configuration.html
+[cdistmatrix]: https://matrix.to/#/#cdist:ungleich.ch
+[cdistmattermost]: https://chat.ungleich.ch/ungleich/channels/cdist