The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
Imagine yourself in a stick-figure toy factory. Your job is to weed out the toy that is unlike the others. The toys are in high demand so you have to be quick! Have fun while improving your eye-hand, ok, -finger, coordination. Come on. Be the world's top weeder-outer.