Its actually amazingly simple. Indeed you extract these files, run an executable, run another batch file, run another executable and presto you have the image. Flash that image to the phone, but running another exectuable and yer done.
The "hard work" is all pre-done for you, indeed that is the beauty of the kitchen. It does most of the work for you. So yes, indeedy it IS that easy.
I'm a sw engineer, and my word of wisdom to most newbies is "if they all ever figure out how simple and easy what we do is, well have to work nights and McDonals. So SHHH dont give the secrets away...
That applies here to guys. Relax... Just about anybody can do it. If you have installed CAB's on you're phone and can handle a command prompt you can do this.