Most codes you receive are used in the in-game market. Once on a city you want to use them on, click on market, then redeem code. Most in game codes are about 10 characters long. If you have issues with a code, please make a post on the tech support saying your code did not work, and you require help. PM the code (just in case it wasn't broken) to the staff member that responds so it may be fixed. Please also note, that codes MAY ONLY BE USED ONCE so be sure you are 100% happy with the town you want to use them on. Items that go into the bank are only for that town and are not transferable between cities.