need more info on what device you have ... but it should be pretty simple...

plug in usb... let it become your soundcard... plug speakers into device....

make sure that output mode is match studio direct...

all sound pc sounds and guitar will come out of your speakers...

in cool edit pro, make sure that are setup to use the Line6 ASIO drivers...

the input and output device MUST be the same...

that's why the speakers get plugged into your device...

it helps control latency and all pro audio interfaces work like this.