This JVC PC-X 1000 is an awesome unit with lots of power.
Be very careful not to mess up the internal circuit and components.
What are you trying to connect?
With very little information it is hard to say what to connect and where to connect.
Take a look at the first pic- on the right side bottom you see 4 RCA female sockets- I would assume it is the CD "line out" and "Phono in" RCA sockets seeing the last picture. There is a ground connection for the PHONO next to it.
Top could be left channel and bottom, the right channel. It is hard to say which is which. Left and right channels are top and bottom. I don't see an AUX connector there.
You can use the "phono in" RCA female socket using a special plug/Input Attenuator and use it as an AUX line in connection. I need to look up where to find those. I don't know if this is a good recommendation.
Hopefully one of our members here who own this unit will chime in.
Be very careful and make sure about what you are trying to do.