Sampling frequency in Matlab

clc;close all;clear all;

%%

[signal,Fs]=audioread('Dn-10.mp3');%Signal input

in mp3 format.

sound(signal,Fs);%Fs(sampling frequency)=44100Hz.

p=length(signal);

c=fft(signal,p);%Fourier transform.

y_n=abs(c);%Magnitude of the FFT.

Phase_c=unwrap(angle(c)); %Phase of the FFT.

x_n=((0:1/p:1-(1/p))*Fs);

w=phase(1:p/2); %Half range of phase of length of signal.

g_magnitude=abs(1:p/2); %Magnitude Spectrum of the signal.

figure(1)

plot(x_n,y_n);

xlabel('Given audio signal frequency in Hz');

ylabel('Given audio signal amplitude');

title('For the given audio signal of frequency response');

xlim([0,1100]); %Bounded the signal 0 to 1100Hz in X-axis.

p=max(y_n);%Find the max value of y_n signal.

q=(y_n==p(1));

r=find(q);

Frequency=x_n(r(1))%Finding corresponding frequency value.

if(Frequency>=100 && Frequency<=325)%The observed characteristic frequency

change for the signal.

disp('The given signal command is Wait.')

else

disp('The given signal command is Go.')

end

Here is simple matlab code to match a voice signal with its input voice signal. Can anyone explain how this code is working?