If you've made some bad purchases from the Catalogue, or maybe you've just got bored with the furniture in your room, you can trade it in for something new with other Habbos.
To trade with someone, open your hand and drag an item on to them. This will open the secure trading box (1.). You can trade more than one item at a time - maybe if the other Habbo is offering something really good.
If you are happy with the items offered, click 'accept'. Once they have done the same, the trade is made and the new items will appear in your hand.
IMPORTANT NOTE: Beware of Habbos trying to steal your stuff - do not click 'accept' until they have dragged their items into the trading box.