That yellow jack you mention on the TV causes me to ask you if you are sure these are outputs (and not inputs) on the TV? This is usually, but not always, indicative of an input.
Most TV's have these inputs to allow connection of external sources such as DVD's VHS machines and cable boxes. Comparatively few TV's have composite video outputs.
If these are indeed outputs, you don't need to connect that yellow jack to the receiver to get TV sound to the receiver. Just plug the red/white jacks into any available input, except a phono input should you have one. Then it should be a simple mater of selecting that input on the receiver.
Also, some, not all, TV's need to have the audio option set, usually on a menu somewhere, to pass audio out of these jacks. Check your TV's manual for this.
But first, make sure they are really outputs.