I connected with my Website but not showing Average Session Duration?

I was about to track the average session duration on my https://internetoffersnow.com/, but unfortunately, I can’t. My friend suggested I sue matomo he said it is best than google analytics. But why I can’t get information about user behavior on my matomo analytics account? Can you please suggest what should I do now to get this feature in my motomo account. I need your help, please.

How did you proceed?