1. Connect a USB flash drive or external hard drive to your Xbox 360.
2. On the Xbox 360 dashboard, go to "My Xbox" and select "System Settings".
3. Select "Storage" and then choose the USB flash drive or external hard drive you want to save the movies to.
4. Select "Configure Now" and follow the on-screen instructions to format the drive for use with the Xbox 360.
5. Once the drive is formatted, you can start copying movies to it. You can do this by connecting your Xbox 360 to a computer using a USB cable or by using a media streaming app like Plex or Kodi.
6. When you're finished copying the movies to the drive, you can disconnect it from the computer and connect it to your Xbox 360.
7. On the Xbox 360 dashboard, go to "My Xbox" and select "Videos".
8. Select the USB flash drive or external hard drive that contains the movies and then select the movie you want to watch.
9. The movie will start playing.
Here are some additional tips for saving movies to your Xbox 360:
* Make sure that the USB flash drive or external hard drive is formatted for use with the Xbox 360. If the drive is not formatted correctly, the Xbox 360 will not be able to read it.
* The Xbox 360 can only play movies that are in the following formats: .wmv, .mpg, .mov, .avi, and .mp4. If a movie is not in one of these formats, you will need to convert it before you can play it on the Xbox 360.
* The maximum file size for movies that can be played on the Xbox 360 is 4GB. If a movie is larger than 4GB, you will need to split it into smaller files before you can play it on the Xbox 360.