Backers can use the "Manage Pledge" button to add the specified amount from each add-on to their current pledge.
Add-ons will be managed through the pledge manager CrowdOx at the end of the campaign. A link will be sent out to all backers who've pledged at least $1. From this link, backers will be able to edit their pledge and choose which add-ons they'd like. Backers can always increase their pledge through CrowdOx to get additional items.