README.md: Misc updates

Author: cgwalters

README.md

@@ -8,6 +8,8 @@ The longer term vision of this project is that the build infrastructure
 upstream operating systems.  For now, this project acts as a more central
 point for this across these distributions.
 
+Current WIP documentation: <https://gitlab.com/bootc-org/fedora-bootc/docs>
+
 ## Motivation
 
 The original Docker container model of using "layers" to model
@@ -16,9 +18,47 @@ aims to apply the same technique for bootable host systems - using
 standard OCI/Docker containers as a transport and delivery format
 for base operating system updates.
 
-## More information
+## Generated container images
+
+At the moment the main image is `quay.io/centos-bootc/centos-bootc:stream9`
+
+## Building
+
+The build process is 95% just installing RPM content into a container
+image; there is some non-RPM config files etc. in this repository
+too.
+
+See:
+
+- [Containerfile.centos-stream9]
+- [Containerfile.centos-stream10]
+- [Containerfile.fedora-40]
+
+For example:
+
+```bash
+podman build --security-opt=label=disable --cap-add=all --device /dev/fuse \
+  -f Containerfile.centos-stream9 -t localhost/centos-bootc:stream9
+```
+
+NOTE: This will not work when using "podman machine" over the remote client
+(e.g. the default on MacOS/Windows).
+In order to do a build on MacOS/Windows, first:
+
+`podman machine ssh`
+
+Then, navigate to your source code directory:
+
+`cd /path/to/source/code` (e.g. `/Users/chloe/src/centos-bootc`
+
+And finally, invoke the same
+
+`podman build ...`
+
+per above.
 
-See: <https://bootc-org.gitlab.io/documentation/>
+There is also <https://gitlab.com/bootc-org/fedora-bootc/base-images-experimental>
+for a new even more container-native build system.
 
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