How to link: A simulink file's parameters file(.m) to the simulink model (.slx file)

I am using the example available in the matlab PVarray_250kW (simulation file) in which I need to modify the parameters as per my requirements. So now the questions are

1. Where should I save my new modified simulation file(.slx) and the parameters file (.m) ? (Either in C: drive where the example file is located or in other driveslike E: or F:)

2. How will I call the newly modified .m file in my new modified simulation file ?

Kindly help me with clear explanation of calling the function inside the MATLAB function block. Detail explanation is much much appreciated