Already have a PastBook account? When you find yourself on the home page, click the button on the top of the page to sign into your existing account or create a new one. A pop-up will appear, asking you to sign in with your Facebook account or email.
If you have already created photo books in past, you should have a unique link to your PastBook. Use it to get to your photo book and sign in by clicking the button on the top of the page.