Step 3: Attach the RCA Cable
You need only one RCA cable. Whether you choose red, white or yellow cable doesn't matter.
1. Cut off the plug from one end and expose the ground and hot wires inside. Hot is the center and ground is the outside. Attach them to two wires as shown in picture 1.
2. The hot wire goes to the single output from the two resistors. The ground goes to GND pin on arduino which the potentiometer shares with the cable since both of them have a ground. Take a look at pictures 2 & 3.
3. Plug the other end of the RCA cable into your TV's video input (yellow color).