Originally Posted by AnemicOak
Make sure your phone is set to allow installations from unknown sources and then install the Amazon Appstore. Once it's installed you can access your apps. As long as they're compatible with your phone you can install them from there...
You can get the Kindle app from the Amazon appstore or from the Google Play store which should be pre-installed on your phone, just search for Kindle and when you find the app tap install.
Thanks, this helped me as well!