Do you know the SSID (network name) and password of the last network your Roku device was connected to? If so, the easiest thing to do is to just configure your new Wi-Fi to match the old. If not, you need a physical remote. If you know the information for the old network then there's also a way to use multiple devices (a phone with hotspot and another phone or tablet) to get it connected to the new Wi-Fi, but you must know the information for the last network the Roku was connected to. Depending on your model of Roku (i.e., if it's not a stick) then another easy solution is to get a cheap universal remote that supports Roku devices. That won't work if your device is a stick that plugs into the TV without the need for an HDMI cable.
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