Get parameters in palabos

Hello every one,
I am trying to simulate non-newtonian fluid flow in Palabos and also I am a beginner!
I run the cavity2d example, then my supervisor asked me to change Nx, Ny,density and etc. but I realized that is some codes, such as cavity2d we use:

const plint nx = parameters.getNx();

to get Nx. My question is where these parameters are defined and how can I change them. I will really appreciate if anyone could help me.

Many thanks

Dear Elahe,
in the cavity2d.cpp, you can find the following code:

IncomprFlowParam<T> parameters(
        (T) 1e-2,  // uMax
        (T) 100.,  // Re
        128,       // N
        1.,        // lx
        1.         // ly