It might be useful to read this introduction to Parallel Computing Toolbox. In essense, you should simply be able to write a parfor loop, and with default settings, Parallel Computing Toolbox will automatically start a "parallel pool" of workers to work on the body of the loop in parallel. You don't need to start the workers explicitly, but you can do that if you wish - the following command will (with default settings) launch as many workers as you have (real) CPU cores on your local machine:
parpool();
