Welcome to the Roku Community!
I'd be happy to take a closer look to see how we can help get you up and running. Is there a light showing on your device? How are you powering the Roku device? Is the device plugged into the TV USB port or is it plugged into a wall outlet? For troubleshooting purposes, have you tried connecting those Roku devices to another TV to see if you are experiencing the same issue?
Please keep us posted and we'll continue assisting you from there.