How do I choose VAD parameters?

The only indication I can find for which parameters to use is vadInitCstParams. I am able to view the source code and see that it has properties such as Fs, M, NP, etc. I understand some of these parameters from the comments, but others aren't clear.

Can I change Fs without changing everything else?

What should be optimized vs. what's that's fine how it is?

Can I get a description or link to a description that describes what these params mean?