After logging into the Registry click on:
Instructor Tools or Training Sponsor Tools,
and either "Mark all as Attended" or "Add Non-enrolled Attendee to Roster" (you will need the training participants' Registry ID #s).
Jump to (06:26) minute on the video for instructions on how to confirm attendance for trainings (videos are currently being updates to match the new website, but the functions are similar). Also, check out this Video Help Sheet so that you can easily see how to add trainings, events, and confirm attendance.