Around the border of the game board there are pieces. Try to place them on the charted way that the half-painted pigs painted on the pieces will it make into complete pigs. This is not an easy step, because the pigs on the pieces looks very alike. With mouse button down, drag the particular pieces to the right place on the board. Before placing a piece on the board, you'll need to rotary it sometimes.
To rotary a piece, place it on the desired field first, and click it several times until it is turned right.