The object of the game is to match two uncovered cards in the pyramid and discard card pile to total 13. A King has a value of 13, so it can be selected by itself. A Queen is 12, a Jack is 11, an Ace is 1, and all other cards are face value.
If the only card covering another card in the pyramid totals 13, then you can select both cards for removal.
Based on what difficulty level you select, winning a pyramid board will be based on the number of passes through the discard pile, if you've cleared the pyramid of cards, and if you have any discard pile card remaining.
