I have a file that pre-processes the video, the main code and then post process the video to put the background subtraction together, how do I call each file so it's only called once?

I have a file that pre-processes the video, the main code and then post process the video to put the background subtraction together, how do I call each file so it's only called once?

I have also tried 'fileName.m'; at the bottom of my main code, that does not work.