When I created my deck, I had to click the button in the top left (that flips the card display style from thumbnails to a tabled list and back again) before the thumbnail with “New Card” appeared.
However, now that I’ve added a couple of cards, tried them out and went back to the cards dashboard, I can’t get the “Add New Card” action to show up at all.
I’m using (the latest I think) Chrome on OS X 10.11
Also, in the Quickstart docs page where it talks about adding new cards, putting a screenshot to show what it looks like in the dashboard would be excellent.