How do I plug the 3 wires from speakers into Dell XSP 8700?

The speakers are HK-595 and have a black lead labeled rear, a green lead labeled stereo and a yellow lead labeled digital. The back of the computer has a blue socket labeled stereo in, a green socket labeled line out, a pink socket labeled mic, and orange socket labeled center out/woofer, a black socket labeled rear, and a grey socket labeled middle surround. The speakers are HK-595 and have a black lead labeled rear, a green lead labeled stereo and a yellow lead labeled digital. The back of the computer has a blue socket labeled stereo in, a green socket labeled line out, a pink socket labeled mic, and orange socket labeled center out/woofer, a black socket labeled rear, and a grey socket labeled middle surround.