if I make them private, How can a certain person be able to see the videos? I want to share with another coach but not all my channel subscribers
When I made them private and shared the link with the other coach, he couldn't see them
There are three ways to publish a video: public (searchable by search engines, visible to the public, and notifications sent out to your subscribers), private (only you see it), and unlisted (you must share the link for someone to access the video). You want to publish it as "unlisted" for what you want to accomplish. When creating the video, you have likely set the default to "public". Simply switch it to "unlisted" then publish it.