There are upside-down cards on the playing field. Turn them over one at a time and try to remember the pictures on the cards.
Try to turn the cards over so that two cards in a row have the same picture. If two cards turned over in a row have the same pictures, they are removed from the playing field - congratulations, you have found a pair!
If two cards turned over in a row have different pictures, the cards are turned back, and you try to remember the pictures on them to open the pair correctly next time.
The game ends when the whole playing field is cleared of cards, i.e. all pairs of pictures are found.