Plug the TRS-to-3.5mm converter into the "Line level" microphone socket, third from the left on the front of the ZS. This converts the 3.5mm socket normally used for line level connections, such as with a microphone, to accept the larger TRS plug, also referred to as a "jack" connector. Electric guitars can only be connected to a jack connector.
Plug the instrument cable into the adapter. Plug the other end into your guitar.
Click "Start" on your computer and select "Control Panel." Select "Hardware and Sound," click "View Hardware and Devices" underneath "Device Manager." Select the Audigy ZS sound card from the menu. Select "Properties" and edit the settings of the line level socket to "Instrument Level." Microphones and instruments have different signal levels. If you don't increase the base level of the socket, the guitar will be too quiet.
Place a microphone stand so that the collar sits directly in front of the speaker on your guitar amplifier. Fit a microphone into the collar.
Remove the converter from the "Line Level" jack on the sound card. Connect the microphone cable to the "Line Level" input on the Audigy ZS.
Connect a jack cable to your guitar input. Connect the other end to the amplifier. Turn on the amplifier. This approach mitigates the need to modify your sound card. Instead of recording directly to the sound card, the microphone records the output from the amplifier and sends the audio signal, rather than line level signal to the sound card. The benefit of this is that you don't need to modify your sound card settings, and you get a more natural sound. However, interference from wind, air conditioning and creaky floor boards is more likely.