First connect your Hdmi Port to your Roku TV and the 2nd device. Your screen will automatically mirror your computer. So you may have to play around with it a bit and plug into each hdmi port separately at the back of your TV, to see which one works. Next, right click on you desktop to locate the "display settings." Under display settings, go to multiple displays and select" extend these displays". After this, select keep changes.
You may have to restart your computer is you dont see the the options. Once your computer comes back up, you should be able to complete these steps. Hope this helps
