Integrate responsive multilevel menu in squarespace

I have a squarespace 6 website that uses the FIVE template. I have bought some code (see http://tympanus.net/codrops/2013/04/19/responsive-multi-level-menu/) that I want integrated in the squarespace website. It needs to work on all modern web browsers. I'm happy to receive accurate step-by-step instructions to do it myself. If job is accepted, I can forward the code I purchased. This includes CSS, JS, images and fonts.