From Aeria Browser Wiki
Personal Backpack: The backpack interface is divided into two parts, the personal profile and the backpack storage space.
Shortcut to Armory: In the top-middle of the backpack interface you can click this button to open up the armory window. This can be done even while waiting in the lobby of a fight so that you can upgrade and improve your gear in-between fights or even stages of an Additional Scene.
Card status and quick purchase: Above the image of your character are four spaces for cards which may or may not be present when you check on your character. Hovering over each with your mouse will tell you what type of card it is and for how much longer it is activated. Clicking on an empty card slot will allow you to purchase a card to increase your experience rate, glory rate or even prevent you from being kicked from lobbies.
Organize: Just above the storage space on the right is a pink button with a tiny wand on it. Selecting this button will automatically rearrange the items in your backpack to fill it from the upper left down. You can do this for both Equipment and Items but the option will not automatically stack items.
Advanced Password: Use this option to add a secondary password to your backpack as an extra layer of security in the event your account is compromised. Make sure you remember it though or else the only way to gain access to your inventory will be to contact a Game Master to help you.
Bound vs Unbound Items: Items that are bound are marked with red text in their tooltip (the window that appears when you hover over them) that reads "Bound." Bound items can not be sold to other players, placed in the auction house or given away. You can either use the item yourself or sell it via the "Sell Item" tool in the backpack. Unbound items are marked with green text in their tooltip that reads "Unbound" and can be sold, auctioned and sent as gifts to other players.
Expired Items: Items that have expired will be darkened out and have the word [Pay] on them. You must renew these items by clicking on them and selecting the option to renew them. Some items can only be renewed with coins while others can be renewed with vouchers.
Currency Items: Across the bottom of your backpack are the 3 main forms of currency in DDTank, Coins, Vouchers and Gold. Coins are mainly used to purchase, renew, and bid on items in the Auction house while Vouchers can only be used to buy and renew some items in the Barter section of the Shop. Gold is generally used to purchase special items before you begin fights, such as Team Heals, Ice Bombs and other skills.
Sell Item: To remove items from your backpack you can either drag and drop them onto this button or outside of the backpack window or you can press this button then click on the item you would like to sell. After using one of these methods, a window will open and ask you if you are sure you wish to sell this items. Sold items can not be recovered but replacements can generally be found in the shop.
Shortcuts: This button decides which skills will appear along the right side of your screen during battles. Items that appear left to right in the shortcuts window will appear top to bottom during a fight and will have the same hotkey.
Split Items: You can only split items while in your Items section of your backpack and you must click this button before clicking on the item you would like to split into smaller stacks. This is useful when you wish to sell only a certain number of items or gift one or two of a large number of items to another player.