Manual STFT to obtain spectrogram of an audio signal

Hi, Im trying to obtain the notes that are on an audio signal by using the spectrogram to know the frequencies on it, but i dont know why this code plots me an empty graph. Can sombody help me please.

[x,fs]= audioread("estrellita.mp3");
dt = 1/44100;
t=0:dt:(117204*dt)-dt;                    
S = zeros(501,117);
windowlength = 1e3;
k = 1;
for jj = 1:117
    y = x(k:k+windowlength-1)';
    ydft = fft(y).*gausswin(1e3);
    S(:,jj) = ydft(1:501);
    k = k+windowlength;
end
F = 0:44100/1000:44100/2;
T = 0:(1e3*dt):(117000*dt)-(1e3*dt);
surf(T,F,20*log10(abs(S)),'EdgeColor','none')
axis xy; axis tight; colormap(jet); view(0,90);
xlabel('Time');
ylabel('Frequency (Hz)');
set(gca,'YDir','Normal')
xlabel('Time (secs)')
ylabel('Freq (Hz)')
title('Short-time Fourier Transform spectrum')

Answer 1

[UMAIR RASOOL]

close all

clear all

clc

[y,Fs]=audioread('black_hole.mp3');

Y=fft(y,Fs);

L= (1:length(Y))*Fs/length(Y);

plot(L,abs(Y))

xlabel('Frequency');

ylabel('Amplitude');

title('(Magnitude Spectrum')

windowSize = 256;

windowOverlap = [];

freqRange = 0:Fs;

spectrogram(y(:,1), windowSize, windowOverlap, freqRange, Fs, 'xaxis');