When Roku says "Live TV", they don't necessarily mean old fashioned antenna live TV. Only Roku TVs can get your local channels and they need a connected antenna. The Roku Channel cannot. If you don't have a Roku TV, you need an app that provides your local stations like YoutubeTV, Philo, Sling, etc.
This article is a few years old, but it has good information:
6 cable alternatives and live TV streaming services (2022)
Roku Community Streaming Expert
Help others find this answer and click "Accept as Solution."
If you appreciate my answer, maybe give me a Kudo.
I am not a Roku employee.