Firstly, log-into your account. This will save any drafts you make for access later.
Find the book you'd like to personalise. You'll need to tell the book builder the name and date of birth of the recipient and the name of the author/s. Then sit back for a few seconds and watch the binary cogs work their magic.
Once your book has been built you can scroll through its pages using the up/down arrows or that fancy trackpad.
Make sure to unlock all of the editable pages by clicking on the 'Advance Edits' button at the bottom left of the screen.
The book builder will give you a hint when a page can be personalised by presenting a little 'you can edit' button at the bottom of each artwork.