How do I make a You Tube video private?
The YouTube service allows for access to videos to be limited to people who have been provided a link, this is a setting called 'Unlisted'.
An unlisted video will not appear in any of YouTube's public spaces (such as search results, your channel, or the Browse page). And the person wanting to view the video doesn't need to have a YouTube account. More about it here on the YouTube website.
To make a YouTube video totally private please read the attached You Tube support document. It is important to note that access to your Private videos will need to be provided through your YouTube account first and that only people with YouTube accounts will be able to access these videos.