Configure your hotspot to match whatever the last network was that your Roku TV connected to - same SSID/network name and password. If you can't remember the last network information or you factory reset your TV or it was never connected to a network then there's nothing you can do without a remote unless the TV supports a wired connection.
Even if you set up your hotspot to match the last known network connection and the TV connects to it I think you'll still have a problem. The last time I tried the app with my Roku device connected to my hotspot it didn't work. You may need another phone or tablet that's also connected to your hotspot. It's probably easier to just run to Walmart and pick up a Roku voice remote. Note that the Roku simple remote will not work with any Roku TV.
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