Help getting started with Roku devices, including setup, connecting your device to your TV, linking a Roku device to your account at my.roku.com/link, adding channels, subscribing to services, and more.
How is your Roku box and cable box hooked up to your TV? If the answer is "via HDMI cable", note that most TV's have more than one HDMI port. You can plug your Roku into HDMI 1 and your cable box into HDMI 2.
When you want to watch your Roku, you switch your TV input to HDMI 1, and to watch your cable box, you switch your TV input to HDMI 2. This is usually done thru the Input button (or similar) on your TV remote.
Yeah, I got some Rokus. https://youtu.be/d1CSEeqWl10