How do you do a shell swap?

I have a broken top screen for my NEW 3ds and I figured I would replace my scratched up housing while I have it apart. The problem is there is no tutorial that says how to actually take it apart. Most links I can find point to the iFixit guide but the problem is THAT TUTORIAL DOESN'T ACTUALLY SHOW HOW TO TAKE IT APART!! It shows where the screws are and some of the board but the critical part - how to take the tiny ribbon cables out and most importantly how they go back together isn't there. The iFixit guide takes the circle pad out but instead of showing the rest it's all like "here's whats inside the circle pad" and the next part the board is out. how did it come out??? how do you get the rubberized part of the circle pad out to put into the new shell? none of these questions are answered anywhere.

I can take apart a DS Lite and put it back together with my eyes closed but I can not figure this out.