How to enable first lesson for anonymous user?

Hello everybody, I want to enable the first lesson for anonymous user? The anonymous user can access to first lesson and learn. But, they can't access to other lesson. If they login as student they can access other lesson. I found the config "Group visibility *" for the course. I think the lesson have "Group visibility *" is better. Because, A couse have many lesson. The anonymous user need to try a first lesson for demo before they want to register that course. How to do it? Thank you so much, Bien Hoang,