First thing to do is go to the Flooded City Coast













Advance until you reach this point of the area and turn right and you'll notice a building that has a path that you can follow behind it.




































You'll find this android behind the building. Talk to him and bride him with money so that you can travel down the elevator behind him.



























Once you've made it down the elevator go straight and talk to the lady behind the desk.













Color set 1 can be unlocked from "Rank E Trial"
Color set 2 can be unlocked from "Rank B Trial"
Color set 3 can be unlocked from "Special Rank Trial"