System modeling/continuous plotting

I am doing a system modeling project where I have a transfer function of the process and I need to control the stability of the system. I have some experience in Simulink but would like to start the project by writing code in MATLAB that will enable me to track a certain property of a variable in my system (position of a ball in my case) so to see how will the system behave when error is introduced (using the step() function). When I run the code, I would like a window to appear which will plot the position of the ball in real time while enabling me to introduce error to the system as the position is being plotted.

So my question is what functions should I use for this and/or would it be better for me to do all of this just in Simulink if it's possible?

This is the trasfer function of the system and for now, simulating the response of the system with the graph, I need to find the proportional (P) gain and time constants of the derivative part since this is a relatively fast process:

tf_ball = -m*g*d/L/(J/R^2+m)/s^2;