If you would like to purchase extra items during the Kickstarter, you can just go to "manage your pledge" and increase the amount accordingly. After the campaign is over, we will send you a survey and eventually a pledge manager to ask you how you want to spend your money. So, let's say you are currently a Captain! tier backer, you should already be committed to $100, and you would like to purchase the Mazu's Dreadful Curse expansion. You simply go to "manage your pledge" and add $40 to your pledged amount, for a total of $140. After the kickstarter ends, we will ask you how you would like to allocate that $140. You can either confirm that or change your mind and purchase other items with the extra $40, or add even more items and pay for them via paypal.