Hello Delma,
There is a MATLAB component in the component library of OptiSystem which you can find at: Default/External Software Tools/MATLAB Library. You need to setup your script in MATLAB and then load that script in the MATLAB Component by defining the path to it. In your MATLAB code you will define the number of and types of ports and accordingly you will have the incoming or outgoing ports, which you can further connect to the visualizers to view your signals.
To get started with MATLAB, please refer to the already build examples which you can find at the location: C:\Users\USERNAME\Documents\OptiSystem 23.0 Samples\Software interworking\MATLAB co-simulation
I hope this helps?
Best,
Saurabh.