add instruction for formatting the USB devices

doc/quickstart/quickstart-hackers.md

@@ -6,3 +6,30 @@ better go [here](quickstart.html) instead.
 
 TODO: quickest possible way to get started for hackers, with any potential
 side-stories being linked to elsewhere in the docs.
+
+**Assuming Raspberry Pi 2 (dm-crypt modules for the Cubox not set up
+  automatically)**
+
+## Prepare the Blimp's SD card
+
+TODO: Explain how to burn the "golden image" with a
+[link](https://github.com/cloudfleet/blimp#blimp) to a detailed
+explanation on how to run Ansible playbooks to explicitly install everything
+(for transparency and reproducibility) on a vanilla Debian Linux.
+
+## Prepare the key and storage USB devices
+
+Also in the blimp repository, in the *scripts* folder is a script to format two
+USB devices with correct labels. It expects a key device path (e.g. /dev/sda)
+and a storage device path (e.g. /dev/sdb) **Warning: running this script on the
+provided devices will erase all data on them. Be sure to back up everything
+important!**
+
+In Linux, run:
+
+    ./scripts/format_usbs.sh <key device> <storage device>
+
+Plug the USB devices into the device.
+
+(on the next reboot the devices will be set up for our LUKS encrypted
+partition scheme)