1. Using RootJunky's SuperTool, root your Fire then install FlashFire
2. Download CM12.1 from here.
3. Follow the instructions listed.
To re-root your tablet or enable ADB:
1. Go to settings
2. Scroll to the bottom, tap on About Tablet.
3. Tap on build number until it says "You have enabled developer settings."
4. Go back and open Developer Options.
5. You now have the options for rooting and ADB.