"According to the latest information from Amazon, here is how to get your categories set up for a Kindle e-book.
First, go to https://kdp.amazon.com/self-publishing/signin
Second, sign into your account.
Third, click the "actions" button for the book you would like to update
Fourth, scroll down to number three, target your book to customers
Fifth, click on add categories. That will open up to a new screen, add or change categories
Sixth, click on the plus button in front of these main categories to open up subcategories and sub-subcategories. Make your selections.
Seven, click on save.
The screen will return to the default page, where you started. Please notice that this is also where you make other changes to your e-book, including editing your book details."
This information is taken from my book, How to Launch a Christian Best-Seller, the John 3:16 Marketing Network Manual, that is only $1.99 on Amazon.
The link if you are interested is:
We just published our first book as a Network that is free, Taste and See, on Smashwords or 99 cents on Kindle.
And if you would like to watch the video about the Taste and See book, you can see it on Youtube: