How to disable my Nikon microphone while using an external (Azden) Microphone?

I wanted to start a youtube channel so I invested in a Nikon D3200 with an external Microphone (Azden ) after recording a few shoots I noticed that there's this really loud and disturbing scrunchy background sound coming from the recording of my Camera's Microphone.

tl;dr: I'd like to disable my Camera's microphone while my external microphone is plugged and recording, how can I do that?

Thank you!

Added (1). I thought Azden had great ratings hence why I bought it! It was really expensive too.

Yes me and my friend thought it was from the Azden mic at first and tried to fix it but after days of work we finally found out that the problem was the Camera itself that records some weird background noise (it sounds like the wind is blowing on the camera)

When you plug in the external microphone, it should automatically disable the internal microphone.

Typically there's an interlock switch built-in to the mic jack so that when you plug in an external mic, it disconnects the internal mic.

Are you sure the background noise is not coming from the Azden mic? Those mic's don't really have a stellar rating.

Here's a quick test. Set up your camera on one side of the room and you stand at the other.
Disconnect your external mike, roll video and talk to the camera.

Do this again with the external plugged in. Upload and listen. One more quick test, have the external mike off the camera, hold it in front of you and talk to the camera. Another one, roll video with the external mike in your hand. Gently tap on the internal mike. If you don't hear that tapping after upload you'll know where the problem is.

If the internal and external are operating at the same time, refer to your owner's manual for instructions or call Nikon for help.

I actually believe the problem is with your external mike and not the camera.