I assume you're trying to add for functions to one of the simple demo programs. Is this correct? If you want to add capabilities such as printf(), you need to start with a project that does some C run-time initialization and includes the libraries. Try running thriugh the New Project wizard and do NOT configure the project for minimal setup. Make sure the ansi libraries are part of the project.
For sensing switches and the like, you're going to read carefully the EVB board's documentation, which should have come with the board. Or you can search the web site for it. The doc explains what ports the switches are tied to, so that you can then use the processor manual and the Codewarrior header files to track down the addresses you need. Conversely, if some of the functions you're interested in appear as light blue in the Codewarrrio editor, you can right-click on them and choose Find this declaration... The editor will take you to the source or header file with the declaration/defintion. Try this with the LED funcitons, which I think are actually macros in this case. Use this fesature to work your way through the various header files, which will give you a feel for where the processor and peripheral reigster declarations reside. HTH,
---Tom