i've got an airport express, a wired router, broadband modem, 2 desktop pc, and a macbook. i would like to set up so that one desktop pc and my wireless macbook to connect to internet. im not sure how to set this up. originally, my modem is connected to the router and other computers connect via router. is it possible to connect the airport express through ethernet port to router, and use its wireless for my macbook? i've tried but no light appears on router to show its connected. if this is not the correct way. how else to set up?