[Jake M]

Well, the actual code files are all of the .c, .h, .lib, and .lkr files. You'll most likely only be working with one or two of the .c and .h files, so you don't have to worry too much about the rest. MPLAB does all the work of putting thes files together for you, in compilation. Just open up MPLAB and then, under the project tab, click open and look for the .mcp file in that folder. It'll list all of the files that are part of the "Project" in a side panel, and you can open them at your leisure.

Now, again, how much do you know about programming.

The .mcp file contains information about the project, such as what files to compile, how they are linked, additional arguments to be supplied to the compiler and linker, etc. The .mcw file is your workspace. It's this file that enables you to close MPLAB and open it up again later, with all the files you were working with still open, and in the same place. But don't worry about that, cause you never even touch these files. The only files you CAN edit are the .c and .h files. And even then, you'll only be working with two or three of them.