I did connect it and the reading I get are wrong
So I think you mean they are not what you expect. What are you expecting?
You will NOT get a reading that is proportional to the volume of the microphone because you are reading in the instantaneous signal of the sound not the envelope of the peak of that waveform.
If you want to measure the sound level you have to take lots of readings and only make a note of the peak reading. The biggest one you find over a period of say quarter of a second will be proportional to the loudness. That will be a linear indication where as loudness is proportional to the log of this value.