The toolbox is free to use, but you will need to have a copy of MATLAB and Simulink installed in order to use it.
Once you have downloaded the toolbox, you can install it by following the instructions in the README file.
The toolbox includes a number of different models of wind turbines, as well as models of the wind field and the electrical grid. You can use these models to simulate the behavior of a wind farm under a variety of different conditions.
The toolbox also includes a number of post-processing tools that you can use to analyze the results of your simulations.