Instructions
Set up your Garment Grid. To set up the Garment Grid, press the "Triangle" button to open the menu. Select "Garment Grids" and select the one you wish to edit. Use the D-Pad to select a slot. A list of available Dress Spheres will appear. Select one to fill the open slot. Repeat for each open slot.
Equip the completed Garment Grid onto your character. From the main menu, select "Equip" and choose the character. Scroll down to the "Garment Grid" option and select the correct one from the list.
Enter a battle.
Cycle through your character's equipped Dress Sphere on her Garment Grid and activate it. To activate the special Dress Sphere, you must first use every other equipped Dress Sphere currently on her Garment Grid. To change Dress Spheres, press the "L1" button and use the D-Pad to select one. Press the "X" button on the Dress Sphere you want your character to change into.
Press the "L1" and "R1" buttons simultaneously to activate the special Dress Sphere. The special Dress Spheres are different for each character. Yuna's is the "Floral Fallal," Rikku's is the "Machina Maw" and Paine's is the "Full Throttle."