How do I share a book?

Summary:

I want to create a reporting book where some parameters will be defined by user POV, and some - selected from the predefined list (prompts). I want to create a sample book with typical prompts, and let the users customize it, selecting and saving their own books with their own prompts.

What level of access do I need to give them, so they'd be able to create their own books without modifying my masterpiece?

Thanks!