Each book in the RAVENFEAST series is published first as a paperback by New Generation. With the cover design from that I upload to Amazon Kindle shortly afterwards (after all, many still prefer the 3D version, signed and dated by the author).
The process is straightforward and you are guided through it by pop-ups etc that take you through the stages to completion. When the book is loaded up, with the cover, you are taken to the next stage. The royalty options are outlined, and the method of payment direct through your bank or through Pay-Pal. Your choice.
Whilst it might be a bit nerve-racking at first, it becomes second nature. There are lots of other options available, and you can set out your Amazon Author Page, with links. I've done that on my RAVENFEAST page here, with links to my own site on Webeden, to my amazon.com author page (I have one for amazon.co.uk as well, with a slightly different blog to the US version), as well as Amazon links to other people's books relevant to the subject matter.
Enjoy the adventure. It's a big, wide world out there. Be a Viking and go forth, embrace the unknown.