I have an insignia flat screen 1080i LCD digital TV, serial number DXAC4Y000086. I just got rid of cable and bought an antenna to get local shows. The instructions say I need to run a "channel scan" or "channel search" and that I should be able to do this by going to "settings" then CHannel set up, the select Antenna or Air. I do not see any of these options in settings. ANy suggestions?