Once you download your new books, how do you read them?
Kindle
If you’re using a Kindle, there are two ways to do this. You can add the books via Amazon Send to Kindle. If you’re using this method, download the .epub file format, instead of the .mobi file.
Alternately, you can connect your device to your computer and copy your book files from Download to Documents (or Books if you have that folder).
iPhone
If you’re using an iPhone or other Apple device, make sure you have the Books app installed, then simply open the downloaded .epub file.
If you want to read the books through the Kindle app on your iPhone or iPad, use the Amazon Send to Kindle feature.
Android
If you’re using an Android device, you probably already have the Kindle app installed. If you don’t, you can download it for free from the Play store. Once you have the app installed, you can use the Amazon Send to Kindle link. Alternately, you can connect your device to a computer and copy the book files to the Documents or Books folder.