Login via live.scu.edu.au. Find the video you wish to modify the visibility of. Then click the box below the video, it will say either Viewable or Private. Change it to the desired option (the choices are explained below the image).
Viewable means that if a user has access to where the recording is located they will able to watch it.
Private means that no one will be able to view it, unless they have been given special permissions to by you. If it is in a channel it won't appear in the channel for anyone viewing it besides you and it will have a padlock next to the name. The video will also be visible in the "Private" view on the left hand side.