Hello,
The microphone will detect the ambient noise, so the noisy output makes sense. With the serial plotter open, I recommend making a very loud noise or blowing into the microphone hole.
The Wireling Scanner might not give useful information since the analog state of High or Low isn't always helpful - the microphone could be detected as a logic Low and wouldn't produce different output from the default "Low" state being output from the program.
Let me know if that helps!
Thanks,
RĂ©na