how can build mat file for to load in simulink

Hello I need to manage my data in simulink true a s-functon builder block , but I need to import this data in simulink I try to use From File block but I have some problem to use it, becouse I need to put inside my data, that is the problem.

My S-function builder block is need to take my matrix and make some specific calculation. I have a problem to load this matrix.

In addition to I need to save my new matrix , after calculation in a new mat file. I Need a good example , please Thanks for the patience and my bad english Have a nice day