How to get a spectrogram of sound using FFT?

Question

Audio

I know that to get a spectrogram, you need to pass an array of complex numbers through FFT. But the question arises - where to get this complex array?
The Internet provides examples of reading a file and converting it to a short or double array, but no one really describes how to cram it into FFT.

Answer 1

Everything is described here: https://www.mathworks.com/help/matlab/ref/fft.html