Auction System:
You can find the NPC which in charging auction in some cities or villages.  This NPC is willing to accept players from different profession dealing with him.
He charges deposit fees for all the things that will be auctioned beforehand.  After the commodity has been sold successfully, he returns the deposit fees, but if the commodity is not sold, the deposit fees will be left to him.
The commodity you get from the auction will be sent to your mailbox, you can get it from the Post Officer.

Browse the Auction Goods:
When you click on the auction NPC, you will see a blank form. You can use that to search what you need. Frequently-used search options includes:
The name of the item: type in the name of the item that you want.
The level range: type in the level range of the item that you need.
The rare rate: select one rare rate you need in the pull down menu.
The profession: select the right profession of the item that you need in the pull down menu.
Usable commodities: display all the auction commodities that suitable for your profession and your current level.
List of commodity classifications: display the commodity classifications that you need.

Bid:
Select the item you want to bid on the browse windows.  The item's quality and name will be listed with its level, the end time of the auction, the person who gives the highest price and the bid price.  And then type your price in the right place at the bottom of the list of commodity classifications.  Then press the "Bid" button at the bottom of the item list.

The Auction Item Display:
The items that you have bid are all displayed in the bid page.  Select the bid tag at the bottom of the interface, you can enter into the interface of checking the item.

The failure of bid:
If somebody gave a higher price than you, then your bid is failed. Your bid currency will be returned by a mail from Post Officer.

The "Buy Now" Price:
A commodity has a "Buy Now" price, if you are willing to buy the item in this price and not through auction, then you get it and the auction is over. You can get the commodity at the Post Officer.

Drag commodities to the auction box:
Press the "Auction" key to enter into the auction interface and open your item box to drag those you want to sell to the auction goods box on the left upper side of the interface.

Set the starting price:
Player set a lowest price according to his own judgement or he can refer to the prices other players have made.

Set the bid time:
The set of time is very important. The longer you set, the more deposit fees you cost.  If your items were sold, you can take back your deposit fees.  But if no one wants your goods, you will lose your deposit fees.  Usually, the shorter of the bid time set (some hours or even less), the less of the risk.  However, if you don't set your time longer enough, other players might not see it.

Set the "Buy Now" price (optional):
This is the most satisfactory price to this item of you.  Don't set it too high, or those who are interested in it will be scared away.

Auction Over:
If you haven't sold your item out when the auction is over.  The auction will stop and you will lose your deposit fees.  The item you want to sell will be reserved at the Post Officer.