To edit an ideabook, go to the drop down menu next to your username at the top of the Houzz screen, choose My Ideabooks. All of your ideabooks should then come up. Choose the book you want to edit by clicking on its title. Once the book comes up, there is a green button that says "edit ideabook". Click on that button and the ideabook will come up in edit mode. The rest it pretty self explanatory.

Thanks! Did it. Wasn't scrolling to the end to find the "Submit" button.