It’s actually really easy. Basically you just go to this website: https://kdp.amazon.com/self-publishing/signin. and follow their instructions.
They give you help here: https://kdp.amazon.com/self-publishing/help
You need a title, description, contributers, language, publication date, publisher, ISBN, categories, keywords, a cover, your book, and some questions about if you want DRM, and have publishing rights for the book.
They even walk you through it here:
http://www.youtube.com/watch?feature=player_embedded&v=ltScSWVLQLk
