I have a 8point fft code done by matlab. WHat should I do to use this 8 point sequence fft to compute a input signal and display it in a spectrogram? I want to use this 8point fft algorithm to read the signal and comment on the frequency spectrum.

My project application requires me to do a real time digital signal processing and its analysis. SO I have decided to read in a real time signal through my micro-processor compute by a set of fft algorithm and comment on the spectral analysis of the frequency content. 1st Problem: How to make use of my current 8 point fft matlab codes, which generated a sequence of number to do a computation on the probably a .wav file. So that I can create a spectrogram out of this computed output and comment on the spectral analysis?