If your pledge is the PDF Master or above, you can add print versions of any book that has been unlocked or released in a print edition. This is called an "Add-On". Check the "Add-Ons" section of the main campaign page to see which books are currently available.
To include a print version of a book in your pledge, simply increase your total pledge amount by the cost of the book Add-On using the MANAGE PLEDGE button. That's all you have to do. Later, when the Kickstarter completes, we'll invite you to a "Pledge Manager" where you can handle your shipping and tell us your shipping address and what this increased pledge total includes.
For example, if you've pledged at the £20 (appx $30) PDF MASTER pledge level, and you'd like to include a print copy of the MINDJAMMER PLAYER'S GUIDE (special Kickstarter price of £15), simply increase your pledge total from £20 to £35.