How to implement Mel Filter Bank Processing and Discrete Cosine Transform?

I have coded the following from pre-emphasizing ,framing and hamming window. But do not know how to go for Mel Filter Bank Processing and Discrete Cosine Transform.Here is a part of the codes:

* * windowsize = Fs/10;
* * trailingsamples = mod(length(s3), windowsize);
* * sampleframes = reshape( s3(1:end-trailingsamples), windowsize, []);
* * 
* * Tf=0.025;           %Frame duration in seconds
* * N=Fs*Tf;            %Number of samples per frame=200
* * n=100
* * w(n)= 0.54 - (0.46* cos( 2*3.14*n / N -1 ))
* * y=s3(n)*w(n)
* * ffts=fft(y,200)
   % s3 is the sampled frequency