I’ve added an extra video to the exercise page.
https://cgcookie.mavenseed.com/exercises/rig-a-crane-arm-exercise
it’s in the text description at the bottom.
That image looks correct, however, you also need to make sure that the current value is updated to what you added in the ‘default value’ there. That might be one thing that you are missing. (and you will need to make sure you run the script too – but I think you have done that)