Roku is installed with tv in family room, how do I use it for bedroom?

It's not clear what you're asking.  If you have a Roku device connected to a TV you can more the device from one TV to another (physically).  If you have an actual Roku TV you'd have to move the whole TV.  In general, you need a Roku device for each TV much like you'd need a DVD player for each TV to watch DVDs.