With this last shipment, we're sending the locks along with panniers uninstalled, in a baggie as opposed to preinstalled. This allows us to better manage stock of locks, and ensure folks get matching ones when needed. A few people have contacted us about how to install them, and where the arm position should be. I've taken the following two pictures to help!
The first picture shows the rear of the lock in the unlocked position. Note the angle of the arm, and how the retaining clip is installed:
The second picture shows where the arm should be when it's in the locked position. It points DOWNWARD, toward the latch release button on the bottom of the lock.