Code Generation Using Embedded Coder eZDSP F2812 using CCS3.3

I have connected to my board with parallel port and have tested some of MATLAB demos. However some demos comprise a script (Mfile) to generate ccs project and code generation tutorial indicated that just pushing "built and increment" to built project. Now I want to built my own project but I a little confused that do I need a script with my matlab simulink or as tutorial indicated "built and increment" bottom will work. In which situations I need to add script and in which situations I do not?!