If you have items to exchange with others, you can take advantage of the trade system to complete it.
Click on trade button, then left click on the target player. If he/she clicks on ok to agree, the trade window will pop out on both sides. Click on "X" or "Close" to close the trading window.
Type the amount in the box, then click on "Confirm" to trade. Be aware that once you confirm the amount, you are unable to change it. The only way to change the amount is to cancel the current trade and resume
Drag your item to the trading window, check if the money is right, then click on "OK". If the other party clicks on "OK" too, then the trade is completed.
Name and level of of the other party:
It shows in the top box
The upper six slots represent the items of the other party, the lower six slots represent your items. Place cursor on an item, you will see its details.
Your money represents the total amount the other party offers. You can put items you want to trade in the lower slots. Remember once it is placed, it cannot be taken back, unless you cancel the trade.