I have a PC with windows 7. I have a Roku express on my TV. I have a samsung 4 android phone with screen mirroring capabilities. The TV is too far away from my PC to hook up an HDMI cable and my PC is only windows 7. I also downloaded Roku to my phone. How do I cast my free TV shows from my phone to my TV? I am not electronically adept and I am having trouble. I need a detailed walk through.