diff --git a/hosts/skycam/README.md b/hosts/skycam/README.md
index de64288..29f932d 100644
--- a/hosts/skycam/README.md
+++ b/hosts/skycam/README.md
@@ -20,3 +20,10 @@ SD card | `/dev/mmcblk0` (ext4, NixOS Root)
 ## Devices and connections
 - Camera Module 3 with wide-angle lens
 
+## Building
+To generate a compressed SD card image for Skycam, run:
+`nix build '.#nixosConfigurations.skycam.config.system.build.sdImage'`
+
+Once a card is imaged, the existing SSH host keys should be copied to
+`/etc/ssh` manually to enable secret decryption.
+