A good starting point would be the toolbox help + examples and the file exchange. E.g.

http://www.mathworks.com/matlabcentral/fileexchange/37998-open-genetic-algorithm-toolbox

http://www.mathworks.com/matlabcentral/fileexchange/34144-simple-example-of-genetic-algorithm-for-optimization-problems

I am not an expert in your field. I suggest you follow these steps:

1) define the objective function of your system based on the parameters to be optimized.

2) Adjust the control parameters of the genetic algorithm

3) Define the stopping criteria of the algorithm.

You can use the proposed MATLEB program that works well.

good luck

Please refer to this article:

http://journals.sfu.ca/ijietap/index.php/ijie/article/viewFile/423/148