Trading is a way that players can exchange items in a mutual agreement deal; the action or activity of buying and selling goods and services. Trading involves more frequent transactions, such as the buying and selling of stocks.
To start the trade interface, you will need to click on the "Trade" tab along with the other action tabs.
You'll notice your cursor icon has changed to the trade scroll, you then need to click on the player you wish to make trade with. The other player you have requested a trade will then need to accept it.
When the trade has been accepted you will have a trade interface pop up like this;
If you wish to trade gold to another player, click on the box next to the gold icon and enter the desired amount and then click "Confirm". Once you have confirmed you can't undo the changes unless you close and re-trade the player again.
The 6 boxes 3 in a row and 2 down is where you will put the items you wish to trade the player, to do this you will need to left-click drag the item from your inventory and move it over to the trade box.