There are multiple systems in which different parts of your metadata are collected and stored.
In Atticus, the information you enter on your Book Details page (Author name, ISBN, title, language, etc) are included in the book's core metadata. You can review your book details by opening your book in Atticus, and clicking on the book title at the top of the left navigation pane.
There is also retailer-level metadata. Each retailer, like Amazon, will have a separate system for entering this metadata that aligns with their catalog requirements, and you'll typically be asked to enter this information when you upload your book to a retailer. This would include your book's description, keywords, keywords, categories, etc.