Hi there, what you are going to need to do is create additional ideabooks and reassign photos from your first ideabook into the new ideabooks and then delete them from the first ideabook. It's a two step process, but hopefully by creating additional ideabooks you will set an easy framework for later.

Check out this previously answered question for a step by step guide.

https://www.houzz.com/discussions/i-created-an-ideabook-but-it-is-becoming-dsvw-vd~20515