King = 13, Queen = 12, Jack = 11 Ace = 1, the remaining cards correspond to the numbers written on them.
The cards are removed in pairs; the sum should be no more, no less but 13. The exception is the King which is removed from the playing field in splendid isolation.
Pairs can be composed of the cards that lie above and are not overlapped by the adjacent ones. Make up pairs, holding the mouse cursor on one of the cards you need and dragging it to the second one.
Removed pair gives you 100 points, each time a series of removed cards adds another 100 points to the previous value.
If no step is possible (necessary cards are closed by the others or are not available) you can click on the stock and find the necessary card. This method can be used two or more times, but each time you lose 500 points. You win the game when the pyramid disappears.