Press the Manage Your Pledge Button. If you have not pledged yet it will say Back this Project.
Increase your pledge in the Pledge Amount box by the total of the add-ons you want to add. Do not change the tier you are currently pledged at, unless you also want to change it while you are on this screen. You will then need to add the total of your add-ons onto the amount of the tier you have just chosen.
If you are an international backer, please remember to add $7 for shipping if you haven't.
Please send us a message which add-on you want.