Confine Screen Edges Does Not Appear in unity

Unity and programming beginners.
I want the camera to track the characters within a certain range.
On the
Introduction to Unity site,
If you click Add Extension in Chinemachine Virtual Camera in CM vcam1 and add Chinemachine Coffiner, a check box named "Confine Screen Edges" appears.
However, this check box does not appear on my PC.It is possible to add Chinemachine Coffiner.
How can I publish the Confine Screen Edges?
Thank you for your cooperation.