Here is the page where I found out how to make it work. If you have a writable CD a thumb drive, use the thumb drive, because it's much easier.
Online multiplayer and some features of Game DVR requires Xbox Live Gold subscription (sold separately).
Stream to one device at a time; streaming with multiplayer from Xbox One requires home network connection and Xbox Live Gold membership (sold separately).
Just download the file, that's all you need to do there.
NOTE: Microsoft stopped updating their backwards compatibility for original Xbox games years ago.
- - - - -AUTHOR'S NOTE: THIS INSTRUCTABLE IS OUTDATED. TO UPDATE YOUR XBOX 360, CONNECT IT TO XBOX LIVE TO UPDATE IT FOR FREE.