You start filling the holes at the bottom row with pegs, and each time you have completed a guess (i.e. filled all four holes) the computer will respond by giving you one peg for each correct color - black if your guess was also in the right place, otherwise white. (But you will not be informed about which colors were correct. That part you will have to figure out for yourself.)

If you haven't managed to guess the sequence by your 8th guess, the computer will reveal it to you and the game ends.