What is free on AppleTV?
I just started free trial of Apple TV. I see many shows marked Cinemax, HBO, showtime, etc. If I watch them will I be charged?
Yes. The free trial is for Apple TV+ (note the +), not for anything else available on Apple TV. For Apple TV+ content, see the following (and also click on the "See full lineup" button) in: https://www.apple.com/apple-tv-plus/