Set up of Roku to HDMI 3 and no signal found

As a newbie, I'd recommend you share far more detail if you seek a solution. Which model Roku and firmware version, brand and model of TV, type of connection (wireless or wired), and where you see the error message and if you've tried using a different HDMI port or new cable to solve it

I'd also recommend you identify which HDMI port on the TV supports ARC (Audio Return Channel) and plug the Roku into that one

Patty2300 

Thanks for bringing this issue to us! We’d like to get more details about your Roku setup issues.

To better assist you, could you please share what @jontalk mentioned earlier? Additionally, to set up your Roku device, connect it to your TV using an HDMI cable, connect it to your Wi-Fi, and either create a new Roku account or log into an existing one. Finally, follow the on-screen prompts to activate the device and add your channels.

Let us know if you need further assistance.

Roku Community Team