The game always starts in the lower left corner. You pick a color to change the tile to. All tiles of the original color that are touching are changed to the new color. You have 35 moves for the first level and your available moves diminish as you progress to new levels.
This particular time waster is a full screen Shock Wave application and it runs very smoothly. I couldn't find a "start over" button, but you can just refresh your browser to start a new game.