Add README with usage instructions

README.md

@@ -0,0 +1,30 @@
+# Babelbox Packer build
+
+This repository provides build configuration and Debian installer preseed files
+for building [Babelbox](https://wiki.debian.org/DebianInstaller/BabelBox)
+virtual machine images for QEMU/KVM and VirtualBox using [HashiCorp
+Packer](https://packer.io/).
+
+## Building the VM images
+
+The images need to be built in separate steps because VirtualBox and KVM cannot
+reserve the needed CPU extension (VT-x, AMD-V) at the same time.
+
+```
+packer build --only=qemu debian-babelbox.json
+packer build --only=virtualbox-iso debian-babelbox.json
+```
+
+## Preparing for Babelbox demo
+
+Due to image size reasons we do not include a Debian DVD ISO image into the
+image. Therefore the VMs have to be booted into the regular OS (first Grub menu
+option). Login as user `demo` with password `babelbox` and download a Debian
+DVD ISO image into `/srv/`:
+
+```
+cd /srv
+sudo wget https://cdimage.debian.org/debian-cd/10.3.0/amd64/iso-dvd/debian-10.3.0-amd64-DVD-1.iso
+```
+
+The version might be different but 10.3.0 has been used for my tests.