I just read the instructions but under "Recording Device I am supposed to select USB audio Codec ,the only choices I have are Microsoft audio mapper-input and my Microphone ?
Maybe the computer did not detect it properly, check in Device Manager and see if it's showing any devices with error in it. Does the system make a new device found ding when you connect the turntable? Look on their support page or through the instructions for anything about the connection and trouble-shooting steps. Maybe check with their support email/phone.
Are you looking to record the records to the computer or to just play them on speakers/headphones? You may need to buy some powered speakers to use with it, Edifier R980T are great for the...