I am forwarding this to our documentation department so they can see about making that a bit clearer. Thank you for bringing this to our attention.
That helps, but the document expressly states that there are three png files to download.
It would be good if there was a sample file to show what we are supposed to be aiming at.
While your documenters are having a look at that point, why not get an expert stylist who has not used this extension before to have a go at following the article and see if he or she can produce a result?
I bet you do not have one who can!