Here you can specify the two parameters of the parameter space.
Select a first type of variable from the drop-down list to assign it to the x-dimension of the grid (independent variable). Then, define the minimum and maximum values of the corresponding parameter, and choose the number of samples.
Note that a large number of samples will slow down the computation.
Finally, select the second type of variable from the drop-down list to assign it to the y-dimension of the grid (dependent variable).