When you launch Google Maps using your Android, iOS, or notebook computer you will see Waldo appear on the left side of the screen (later on he will be available under the menu). When you select Waldo it will launch the game and will be taken to different parts of the globe. Just like in the books, you will need to find Waldo (and 4 of his other traveling friends if you would like to). Once you find Waldo it will unlock the next location. To move around on the map you can use your mouse or the directional arrows on your keyboard.
I never knew that in England (where the puzzle books originate from) it is Where's Wally? In the US and Canada they changed the name to Where's Waldo!
Embedded below is a 1 minute and 31 second YouTube tutorial I created.