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.
In this game there are a grid of letters on the left and a list of words on the right. Search for the listed words in the grid of letters. The words may run from any direction, left to right, bottom right to top left, etc. Use the mouse to drag in the grid to mark the words. The faster you find all of the words, the higher your score.