To play Minesweeper, run the PLT Games program. (Under Unix, it’s called plt-games).
Remove all the tiles that have no bomb underneath. When you remove such a tile, a number appears that indicates how many of the surrounding squares (up to 8) have a bomb; a blank means zero bombs, and the game automatically uncovers all surrounding tiles in that case.
Right- or Control-click to flag a tile that you think has a bomb, so that you cannot accidentally uncover it. Right- or Control-click again to remove the flag.
You don’t have to use flags. When all of the non-bomb tiles are removed, the game is over, and the clock stops.