First of all you must had bought credits in the store (laden), you must look in this message board for anybody who wants to get a interchange with you, you will post the character that you want and the character that you offer, and you must wait for the requests and choose the one that you like then you must put you character on a private sale with the other one for 50clintz and he/she must do the same for you.

Advise: check that the player who you will trade with, really has in his/her possetion the character on bussines!!