Matlab DWT H-level

I'm trying to implement some watermarking algorithm found in a paper. This is a line of the paper:

    *Do the H-level DWT for all the renumbered segments.*

Then in simulation section the author explains the wavelet used for experiments.

    *DWT transform adopted the common wavelet "Daubechies-1" and level H = 3.*

I just don't get what does H means, how do I input H=3 in matlab DWT function?

My actual code is:

[cA,cD] = dwt(audio,'db3');

Can someone help me?