README.md: extend

README.md

@@ -1,6 +1,18 @@
 # Demonstration base images for use with bootc
 
-This repository contains "base images" suitable for use with github.com/containers/bootc
+This repository contains "base images" suitable for use with [bootc](https://github.com/containers/bootc).
 
-These images are considered experimental.  The intention is that these images are
-generated by the OS vendor or distribution.
+These images are technology demonstrators, not for production use.  The intention is that these images are
+generated by the OS vendor or distribution.  Or, you can fork this repository and generate your own
+via `rpm-ostree compose image`.
+
+
+# Building
+
+Here's an example command:
+
+```
+$ sudo rpm-ostree compose image --authfile ~/.config/containers/myquay.json --cachedir=cache -i --format=registry oscore/manifest.yaml quay.io/cgwalters/fedora-oscore
+```
+
+More information at https://coreos.github.io/rpm-ostree/container/