You can access My Media from Media Space, or within Canvas Compass 2g or Moodle as the course allows.
Kaltura recognizes your netid and presents all video and audio files you have uploaded to the database. You can adjust which videos are displayed by clicking on the Filters button:
For example, if someone has made you co-editor of a video, you can find it by setting the filter to "Media I own."
From My Media you can select a video to edit or to publish within that application. For example, within Media Space you can publish to a Media Space channel, but you cannot publish to a Canvas or Compass course from Media Space.