define parameter values for simscape model

I'm playing around with the inverted pendulum simscape file that comes with MATLAB, but I notice some issues:

All the parameters are defined symbolically. For example, the dimension of the pendulum is L,L/12,L/12. However, the simulation can run without me specifying the exact values for these parameters. (I'm only showing the screenshot of the plant---there is a PID control loop that wraps around it). Why is this the case? I'm so confused. The variables in my work space are literally cleared and empty

Answer 1

[Sulaymon Eshkabilov]

Note that all parameters of the examples are predefined (e.g. modelling - > model properties as callbacks) and initiated automatically while executing the model.