Cable box connected to the tv. We don’t know how to switch back and forth
Roku tv
@Blahblahblah2 Is the cable box connected by HDMI or coaxial cable?
Coaxial
@Blahblahblah2 On the Roku TV go to settings, TV inputs, select live TV and set up input. This should put an app on the home screen called Live TV. I don't have a cable box so I am not sure of the exact remaining steps but follow the prompts on the screen that match your situation and it should work. If you have an HDMI out on the cable box the setup is much easier and the picture quality from the cable box should be better with HDMI.