Instructions
Check your cable box for audio and video inputs. It will be labeled, and you'll see a yellow port labeled "Video" beside white and red ports labeled "Audio L" and Audio R."
Plug each of the three RCA plugs into the ports that match their colors.
Plug the other side of the AV cable into the AV Multi Out connector. This is located just above the power cord's spot.
Connect the Wii to a power supply and plug in its sensor bar.
Turn on your television.
Press the "Input" button on the cable box or television's remote control to switch the input from cable to the Wii. Each brand has slight variation on how this works, so if you are struggling, check the user manual for your cable box or television's specific instructions.