Well, on your PC (or Phone), you can download on GitHub something called "Roséverse Installer". It's an app that not just installs Roséverse, it also let you actually switch between Juxt and Roséverse easily in a single press of a button. Download Roséverse Installer on GitHub, then put the file on your wii u's SD card (To be exact, put it on "SD:/wiiu/apps" folder), and there you go!