The Rule Machine interface is a bit non-intuitive the first few times you create rules like this.
On the Action, choose Run Custom Action, then, for the Capability, choose Actuator. Then choose your device, and you will see the commands listed, just as they are on the buttons on the device’s page.
I personally use Jason Bottjen’s (@JasonJoel’s) Component driver for this same device (26933). It splits the device into two child devices, a dimmer and a motion sensor. Function is the same in both drivers, but, to me, it makes the rules clearer because of the logical separation of the devices.
