How can I get the power spectrum using fft function?

I have tried to follow the procedure in https://uk.mathworks.com/help/matlab/ref/fft.html however, I still could not figure it out. Could someone kindly please assist me with this?

clear; clc; A1=1; %Amplitude multiplier A2=0.90; %Amplitude multiplier f1 = 122; % frequency of the first sinus f2 = 44; %frequency of the second sinus fs = 1000; %Sampling frequency t = 0:(1/fs):1; S = A1*sin(2*pi*f1*t) + A2*sin(2*pi*f2*t+5); plot(t,S);