There are many ways to send personal content such as ‘side-loaded’ (aka non-Kindle) books to your reader. You can email them to yourself, use a Calibre plug-in, or you can use the Send To Kindle app from Amazon. I have found this is the best method for me because there is no time delay. Sometimes, when I email or use a plug-in, the book does not appear right away. The app sends the book instantly, and the book is backed up the Cloud as it sends, so you can sync across devices and save notes and annotations. Your personal book will have all the same features as one you purchase on Amazon.
Here are the steps you need to follow:
1) Download the app from Amazon. I use the Mac version, but a Windows version and browser-based version are available too.
2) Set up the app. If you are not prompted to do so the first time you open it, just click on the options wheel. Then go to ‘registration’ and put in your Amazon account information.
3) Leave an icon for the app somewhere convenient; the desktop is a good place. I have it in my macbook’s menu bar.
4) To send a book using the app, just drag the icon for the book on top of it. If you are using Calibre to store your books, this is easy. Highlight the book you want, right-click (or command-click on a mac) and choose ‘open containing folder’ from the context menu. The folder will pop open and the book should be right there.
5) And voila, drag away. A menu will pop up with options to edit the author and title, and select which device to send to. Press the button, and away it goes.