In Chapter 1 when you go to Kilika you have the opportunity to begin a small mini-game. In the first dock section on the East side you should be able to find a woman in blue and some children playing with a Squatter Monkey. If you talk to the woman she will ask you to look for more wild monkeys in the Kilika Woods. When you enter the woods you'll need to go to the locations on the map below and press X to search for the hidden monkey. The object is to find all 13. Once you've done that you'll have to wait until Chapter 3 when you'll go to talk to the woman again. If you found all 13 monkeys she'll reward you with the Chaos Maelstrom Garment Grid.