You don't have to be technically competent, you have to become technically competent :)
construct.net/en/make-games/manuals/construct-3/plugin-reference/array
So it will look something like this
choose(rgb(Array.At(0,0),Array.At(0,1), Array.At(0,2)), rbg(Array.At(1,0), Array.At(1,1),....))
Check the console for errors (F12 in chrome) it will tell you if your ajax is working or not.