I believe we strayed a bit due to my mention of moonreader.
However some info on the install of Google Play and associated files on a generation 8 Fire HD 8" OS 6.3.0.1 (latest from Amazon)
Download of all files from:
https://www.xda-developers.com/amazo...le-play-store/
All went well. At first file install I got a message from the OS that file was not compatible but it installed. I installed them in the sequence shown. The The Play Store app appeared on the desktop. However the Google store would not allow me to sign in. I rebooted the Fire. Same result, the store does not allow me to sign in. Tried many times. I'm sure I entered the correct username and password. Now an interesting item. Google sent me an email saying I signed into their store using my new Amazon Fire 8"HD however I can not get pass their sign in page. I deleted the Play Store file (4th in sequence) and reinstalled. Same results. Oh, well...