To connect the TV's headphone output to the hi-fi system's input, use a suitable cable to connect the TV's headphone socket to the stereo system's auxiliary (AUX) or line (LINE IN) input. Your stereo system has an auxiliary input for connecting an external device such as a television.

If the TV headphone output is a 3.5 mm jack socket, you will need a 3.5 mm jack to RCA cable (or jack depending on the input available on the system). It is important to check that the TV headphone output volume is set moderately to avoid sound saturation.

To sum up, you can connect the TV headphone output to the stereo system's auxiliary input using a 3.5 mm jack to RCA or jack cable, depending on the inputs available on the system.