While you cannot save a page as a template, you can duplicate a page in your book to reuse with new photos and styling.
First, Check Out your book before managing any structural aspect of it. Book check out is required to ensure that page order, page deletion and portrait page updates will not negatively affect the work of other team members.
Select the page you wish to reuse as a model for new pages. Click on the ... icon in the top corner, then choose duplicate.
A copy of the page will be created next to the original. Repeat this as many times as you need.
Once you have completed duplicating the page, check in the book so that your team members can continue working on the book.
Launch the pages in the editor to re-customize.
Drag in new photos and edit the text.