hardware config

I HAVE FITTED AN ATX PRO MOTHERBIARD INTO CASE, I HAVE NOT GOT THE SOUND PORTION OR ATTACHMENT WITH RIBBON CONECTORS TO PLUG INTO SOUND AREA OF BOARD SO I HAVE FITTED A STANDARD SOUND CARD ONTO THE BOARD INSTEAD.
THE PROBLEM IS I CANNOT GET ANY SOUND FROM THE MACHINE , COULD YOU TELL ME WHAT PROCEDURE I MUST FOLLOW IN ORDER TO USE THE NEW SOUND CARD RATHER THAN THE BUILT IN ONBOARD SOUND DEVICE,
THANK YOU
GARY DE VINI