If you don't have any experience at all, this will not be easy to do. But scenery creation in X-Plane is very easy to get into, just grab WED and start doing it. With some basic technical knowledge and after your first working self made scenery you should get the seasons ready easily.
You will at least have to know how library.txt files and virtual paths are working, you will need some skills reverse engeneering John's (or my own) library files to get the idea behind the concept, and, of course, you need some image editing skills for changing the ortho's seasonal colors.