changable variable in simulink

Hi .

In Simulink environment, I want to implement the transfer function, but the problem I have is that the coefficients s and s ^ 2 are VB and VS, which are voltages that are measured from two sources and are constantly changing.

I wanted to understand how the two VB and VS voltages that were measured were to be defined throughout the MATLAB environment set as global, which I would constantly change when I define VB and VS in this transfer function.

Thankful