Go to the exchange merchant located at the HQ of each race and select [Create Inventory]. At first, you need to pay a certain amount of money (100,000 as of current) to open one inventory (20 slots). You are required to set a password and a hint for the password.
In order to use the inventory,you must click [Use Inventory] and enter the password you provided.You will not be able to access your inventory without the correct password.
An interface just like the usual inventory interface will appear after going through the personal identification process. Use drag & drop to move items in and out of the inventory. No fees are incurred for storing items in the inventory but you will have to pay 5% the cost of any item you wish to redeem from the inventory. (No fees are applied for depositing/withdrawing game money (gold, money).)
