First problem it make sure you understand there are jacks and there are plugs. the jack is another name for a SOCKET that the plug fits into.
The picture shows a breadboard with one connection to a jack. It is missing the ground connection to the jack.
Your headphones have a PLUG that will be pushed into the jack on the breadboard.
You ask about the resistor. Try the layout as shown BEFORE trying any modifications.
The whole design is NOT for stereo audio signals.
Does that help at all?
Paul