A KDP kit lists each field of KDP's Details, Content and Pricing pages, in the order KDP asks for them, filled from the edition. Copy each value into KDP and upload the files the kit links to.
The studio never uploads or publishes anything for you. You publish from your own KDP account.
What you need: the edition's details, its AI answers, a built and checked file for each format, a cover and a price.
What you get: one kit per edition with a section for each format. Anything still missing is marked, with a link to where you fix it. You can download the kit as a Markdown file to keep.
KDP in your language: KDP's site comes in English, German, Spanish, French, Italian, Portuguese, Japanese and Dutch. Choose the one you use it in next to the download, and the kit names each step, field and option the way KDP's pages do in that language, with the English beside it. The words come from KDP's own help pages; where they don't say, the kit keeps the English. What you paste (the title, the description, the keywords) is the edition's own and doesn't change.