If you're new or new-ish to Kickstarter, you may not have realized that Kickstarter does not work like a regular online store. You can't fill a cart with the things you want and then see an itemized list afterwards. Instead, Kickstarter works with Reward Levels, which have a specific set of items in them. But because we offer things outside of those reward levels, and because you might want a different mix of items, we use third-party pledge management software.
Once the Kickstarter closes, there's a period of time where the payments get processed. After that, we set up a pledge store on Game On Tabletop, our third-party manager of choice. Your pledge gets imported from Kickstarter into Game On, and that's where you can add more items or even change your pledge level entirely. It's also where you can pledge late, so if now is not a great time for you to pledge, don't worry! You don't have to miss your chance!
Look for details in the updates following the close of the Kickstarter.