Signal Analysis using the Short Time Fourier Transform

I'm trying to analyse some data with the Short Time Fourier Transform using the codes below. Plotting just the spectrogram gives me a colourful figure which does not give that much insight into the data. So I'm trying to get different plots out of it. Eg plot(F,abs(S(:,10))) which I assume is plotting frequency F versus the 10th column of STFT values. Can you please tell me how do I get the absolute value of the frequency on the Y-axis.

I'm also not sure whether my approach is right. Is there any other way to extract data by processing the signal?

Thanks

if true
  clear all
Array = csvread('Wheelflat-63dB.csv');
dt = mean(diff(Array(:,1)));% sampling period
Fs = 1/dt;
[S,F,T,P] = spectrogram(Array(:,2),3000,2800,2000,Fs);
surf(T,F,10*log10(abs(P)),'EdgeColor','none');   
axis xy; axis tight; colormap(jet); view(0,90);
xlabel('Time (s)');
ylabel('Frequency (Hz)');
plot(F,abs(S(:,10)))
end