Before you actually see any download items in the game, you must first import them from the Title screen. After you purchase and downloaded the item from the PlayStation store, start up your game and select 'Import"
Select the third option, "ダウンロードアイテムインポート" Download Item Import, to start the process.
Select the first option, "インポートアイテムの選択" Import Item Selection.
Select the items you want to import. The first page will list weapons, the second page will list clothing. When you select an item, its name will turn dark purple. Go back to the previous menu.
After selecting the items you want to import, Select the second option "インポートの実行" to start importing. It will pop up another screen which will say that the save data needs to be updated, select はい to start.