Where to hook rca cable to on car stereo?

On the back of my stero I have 3 seperate red and white ports for an rca cable but im not sure which one to use.

The three ports are
- rear audio out
-bus audio in
-front audio out

Which one of these do i need to hook my rca cable up too if im install subs and an amp.

Thanks!
1 answer 1