Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
In a nutshell:
1. External Blu Ray Drive
2. Download Handbrake
3. Download a ripping software - (I use MakeMKV (which costs money))
4. After you rip, use handbrake and use either Apple TV 2/3 preset or iPad preset.


Visit the Apple TV forum to do some research.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.