housefly

Ok I am last in line when it comes to understanding computer hardware. I was given this ATI all in wonder and I installed into my computer. That part I could handle. When I play cd and dvd everything is fine. But when I hooked my tv cable in, I got video but no sound. I have read that you need to connect your ATI card to your sound card. Unfortunetly I don't understand how to do that. Can anyone, please help a drowning caveman. Thanks