Start a game, then go to the red glowing circle and press X. It will teleport you to a room with two weapons spinning on the floor. Pick these weapons up and press X to open the customizer. Once inside, move to "Equip". Press X(2) and you should see one of the weapons become highlighted. Press TRIANGLE on the weapon and select "Return to elixir". This gives you more elixir to customize your body. Exit this screen and the weapons will reappear on the floor beside you. Repeat as desired.