Next step is to Confirm Content Rights. You tick a box to say that you have a right to upload the material. On a side note, if there is any suspicion on this then Amazon will email you and ask to confirm that that you are indeed the author or you own the rights. You need to select whether you have worldwide rights for all terrorities or individual ones. If it is the latter, you can select each country/territory. Click save when you're ready.
It moves on to the next step which is to upload your book. The format must be MS Word, HTML, or PRC format. This should only take a few seconds. A little message will appear saying the document was successfully converted. You can now preview it as it would appear on a kindle. Always do this, it shows exactly how well (or poor) the conversion and formatting has worked out.
The final step is to set the retail price. It cannot be lower than .99c - at least for independently published writers. Publishing houses are able to contact Amazon and set an Ebook as free for marketing purposes. This can be a bit of a setback for indie writers but there are other sites that allow you to set your price as free, such as Smashwords. I should point out that anyone who purchases a kindle book outside of the U.S. has to pay an extra $2.50 or so which means even a free book will cost something. A .99c (a bargain in the U.S.) will be $3.51 for anyone purchasing outside of the U.S. No longer an impulse buy, this takes a chunk out of the market for Indie writers so bear this in mind when you are pricing your work. It has a value but building up a readership is vital for a new Indie writer.
Next you save the entries and then press publish. Amazon will inform you that your work is being processed - I forgot to copy the exact text the last time I used it - but it has to be accepted before it can be published. This takes a few days. If it is accepted then it will say Publishing "Your Book". Your content is being published. Most titles take 24 to 36 hours to become buyable. Apparently this is because it takes time to set up a dedicated page and all of the information that goes with it. Once the book is available to buy, it goes live and you can either edit it or click on the link to see the official Amazon page. Remember that any updates will take the same amount of time to become available again.
You should seriously consider creating an Amazon Author page to link up with your books. It makes it easier for people to see information on the author. You can add photos, a bio and even a blog feed or you can blog on the author page itself. It's another handy marketing tool, take advantage of it, it's free.