How to edit the NoName tag in a book

I am new to Framemaker and have inherited a book file where the structure is not valid. It has a high level tag of NoName and BOOK-COMPONENTS for each .fm file it contains.

I want to know how to edit these tags so I can make this have a valid structure. I have searched the help and have found the following advice:

'A new book file has a structure with a highest-level element called NoName and an element called BOOK-COMPONENT for each document and generated file you added to the book. When you update the book, the elements for structured files change to the tag of the highest-level element from the file.

In most cases, you need to make a few corrections in the structure of a book file after updating. For example, you should change the NoName element to the highest-level element defined for the book. And if any file elements are still called BOOK-COMPONENT, add structure to those files and then generate and update again.'

But it does not say HOW to do the above. Can anyone please help me?

I can still generate a PDF file from this information but I'd really like to know how I can make these source files structurally sound.