To receive your reward, you need to fill your postal address, ideally at the end of the donation process, to ease the task of the project owner.
You can always Edit or add your address from your account. First login to your Ulule account and then click to your name/username on the top right corner of the screen and finally on the “Transactions” link. On the desired donation, click on the "Edit address and preferences" line (the pen shaped icon).
A recap form will be displayed and you’ll be able to indicate your postal address.
Please note that from this page you can also change the setting to appear as anonymous for that donation.