you can insert a puzzel using the most left tool in the forum toolbar.
Puzzles

Please see http://www.chess.com/article/view/how-to-use-the-chesscom-diagr for more information on using the Game and Diagram editor on Chess.com.
Please see http://www.chess.com/article/view/how-to-use-the-chesscom-diagr for more information on using the Game and Diagram editor on Chess.com.
How do I make one?