the title says all, I know how I can play this game, because I play it in windows 7, but now the title says I can't move that

Hello,
I am not sure which problem are you having moving the Bishop. Can you describe in more detail? What happens / what do you expect to happen? Where are you moving and from where?
As a reminder, the Bishop moves diagonally. In fact you can even always press V on a piece and see where it can move at a given moment.

thanks I know my problem, in my play.

Could you be more precise please ?

Normally you press enter or click on the piece you want to move, and then press enter or click on the square where you want to drop the piece.

On windows client 3, you can even do drag and drop with the mouse.

If the piece don't move, it's probably because you are attempting an illegal move.