Try it out. Clicking on locations in the world will change them from unoccupied to occupied (and back again), so you can start with any arrangement you like. Then click on the left button to see what happens after one time step, or on the middle button to run through ten time steps at once. You can click either button again to keep going as long as you want. There is also a control panel if you want to do some fancier things. Either way, let's go.
The Game of Life was invented by John Horton Conway, a British mathematician, and described by Martin Gardner in his Mathematical Games in Scientific American in 1970 (Scientific American 223(4), October, 1970, pp 120-123). The game itself continues to be actively explored (see Paul's Page of Conway's Life Miscellany for current descriptions of findings and links to other Life related websites).