Mark the piece that you whish to move by click on it. Then mark the square that you want to move it to. Then you push the button
Castling: Move King two steps
See to it that your and your opponent's email is correct then push the button
eChess remembers the gameboard and your emails throughout the game. The emails is solely used for this game.
Pawn Promotion to Queen or Knight
eChess does not check if your move is legal or not, so it's up to you to play fair.