Go back into your book on your bookshelf, select your book and edit the categories. Don't forget to select publish when you've finished or they won't go through. You may be able to do it through Author Central, but I've never tried it that way myself. Perhaps someone else can confirm that.
I have come to the conclusion that some parts of this system work, but only if you assume that Amazon Inc. uses
many different platforms and databases to do the same job, and the results appear on one single website. That
would explain why this whole thing is a sort of labyrinth. I just put my books in and stay off Forum. As soon as I can
figure out how to put my stuff on Adobe, which would be Digital Heaven for me, then I can really do good things.
Otherwise, I will have to "go" with an alternative, normal publisher, who is not known. That is no issue,
but will take time. I commune with them by regular mail If I can put my stuff on PDF, is that it? then it will
suffice for Create Space. It takes a bit of money. A voice is telling me to "do" it sans preamble.
Like you, I've long suspected that only some of Amazon's databases actually work, but the problems seem to revolve around guessing which ones work or don't, and getting A'zon to admit to it, even if we guessed it correctly. We all have our suspicions, but will probably never get proof one way or another. In the meantime, the conspiracy theories and generally discordant mumbling will continue. A labyrinth, you call it? Yes, that fits it well.
Until you find your digital heaven, please don't stay away from the community for too long. I always read your posts with much interest and enjoyment, even if sometimes, I confess, I haven't the foggiest idea what you're talking about.