Thanks for posting correctly although you could have modified the original post.
Fading is just changing the RGB values from one set to another. Look at some pages on colour theory. Treat RGB numbers like coordnates in three dimensional space.
But most importantly of all learn how to read the code and what those statements actually do. That code is example code that shows you how to drive the hardware, can you seprate out what functions do what? I am sure you are not expecting other people to write your code for you, so look at the tutorials and especially the blink without delay technique, you will need this to do two or more things seemingly independently.
If you have any specific questions then please ask.