Hi,
i think so, many parts need to be updated there
it is an array used inside the action and the info is indeed confusing.
It should say something like : set the ammount of layers you wish to check.
or something similar.
On 'Layer Mask set the number of layer you want to check (you can change later if you need more or less) and press enter
Then below it there will be Elements, click on them and set the layers you want to detect.
If you want to ignore layers instead of Detecting them then you need to check invert mask.