For some, it might seem logical to follow the power through the gear train and understand how the date mechanism works. Suppose that’s not immediately apparent to you (and I don’t blame you, it’s quite tricky). In that case, Smith has shared an illustration (shown below, with parts labeled with letters) and an explanation (which I’ve slightly expanded).
The system starts at the calendar drive wheel marked “A,” which rotates once every 24 hours. As it rotates, it carries the loading cam “B” through a pin in the cam, which is set in the slot of wheel “A.” As cam B rotates, it presses on the lever “C” (which is also attached to the a “beak” labeled “G” and puts force on that “C” lever in a counter-clockwise direction. At the opposite end of this interaction, the “C” lever moves the beak “D,” forcing it to ride counter-clockwise horizontally along the edge of the tooth on the calendar date ring “E.”