Unlike all other chess pieces, the Pawn moves and captures in different ways.
The Pawn captures on a forward diagonal, one square on the right diagonal or one square on the left. It can only capture if the diagonal square is occupied by an opponent's piece. If the diagonal square is empty or is occupied by a piece of the Pawn's own color, the Pawn cannot move to that square.
The diagram shows the White Pawn on the left side of the board with three possible moves -- it can advance one square or it can capture either of the Black Pawns on the diagonal. The Black Pawn on the right also has three possible moves.