Hi - I could use some help. I have an iMac and just purchased an airport express. I must be a dummy setting it up but I am just not getting it. I have a router with the cable line plugged into the wall and router. I have a blue ethernet cable plugged from the router to my iMac giving me internet access. I would like to use the airport express mainly for airplay to my livingroom TV for the Apple TV, but I'd also like to set up a wireless network. Do I keep the blue ethernet cable plugged into the back of the iMac->router, or plug it from the router to the airport express? Or do I need a second ethernet cable? I do need to keep the router, right, since it's plugged into the cable line? Sorry for sounding clueless. Any assistance would be great! Thank you.