I cannot find the Deck Editor. Where is it?

The Deck Editor is shipped together with Wiz Solitaire. When you download and mount the dmg archive, you’ll find these files:

WizSolitaire-*.dmg contents

Typically, you should drag’n’drop the whole WizSolitaire folder into your Applications directory. In this way you’ll also install the Space deck, which you can use as an alternative to the Standard one (other decks are available for download).