We understand that you want to use the Roku mobile app to control your Roku device. To provide you with the necessary assistance, we require additional information regarding your current setup. Kindly confirm if your Roku device is currently connected to any wireless network. If not, we regret to inform you that it is not feasible to connect your cellphone to your TV without Wi-Fi. To establish a connection, you will need the Roku remote to connect your TV to Wi-Fi. Once connected, you can proceed with connecting your cellphone to the same network to complete the process.
You can purchase a compatible replacement remote for your Roku device from the Roku website or a third-party retailer.
Re: Connecting my cellphone to the TV without WiFI
It will not work with the Roku app remote. I don't have wi-fi at home only my smart phone. My TV is not smart. Its connected to the Roku using a HDMI cable. A mobile hotspot connects my phone with the Roku. I using the castify app to cast and stream stuff on my TV. It has a Roku remote option that works great without wi-fi. Most other Roku remote apps dont work well, or have little options unless you subscribe to them