Hi @wtf2,
Greetings, and welcome to the Roku Community.
Thank you for reaching out for assistance with setting up your Roku TV and Onn Roku Soundbar. We are more than happy to help.
To set them up correctly, please connect a single HDMI cable from your soundbar to the HDMI ARC (or HDMI eARC) port on your Roku TV. Ensure that both devices are powered on. Once your Roku TV recognizes the soundbar, it will automatically begin the setup process. Just follow the simple on-screen instructions to complete the connection.
For more detailed information and guided steps, please visit this support article at How to set up your Roku TV Ready soundbar
Keep us posted.
Thanks,
Jharra
Jharra Q.
Roku Community Moderator