Turn on the computer or digital recorder device you are going to use for recording. Make sure the battery is fully charged or there is an outlet to power your device so it doesn't shut off in the middle of recording.
Select "Preferences" on the menu for your recording program if you are using a laptop computer to record your audio. Select "Built-In Microphone" on your audio input menu that will come up. Save that option and close the preferences window.
Select "Built-In Microphone" on your digital recorder if you're using that to record your audio.
Place your laptop across the room from the instruments you are recording. Select a new track on your recording program and do a test recording using the built-in microphone. If the audio comes out clear and non-distorted, you are set to record using the built-in microphone.
Place your digital recording device across the room from the instruments you are recording. Record a test track on your digital recorder using the built-in microphone. Check for non-distortion on the audio when listening to a play-back of your test track.