In her book, she has many lessons which are samples of how to do this type of writing lesson with your children. When I discovered this method, I first used her examples from the book and had great success. Then I learned to do the same with the very books and subjects we were studying. I highly recommend this book for all subjects, but particularly for the language, spelling, and writing sections. It's a very gentle introduction for young children into the art of language.
Narration can be different things from very formal to very casual.
We use both in our home school. Casual narration would be what I like to do with the younger children, but I do not throw it out altogether for my older children either. My children enjoyed acting out the parable of The Good Samaritan and many others. If I use casual narration with my older children, I may just ask them what they read about in their books today or what happened with The Princess in the book Laddie . Another idea for informal narration might be a demonstration of what was learned if the book was about a subject like bird watching or cooking or horsmanship.