Don't you have the instructions?
Your post isn't clear, is it headphones(surround effect) or 7.1 speakers you want?
If its headphones, connect the 3.5mm Jack to the line out 1.
If its 7.1speakers, line out1 does the (fronts), line out2 does the (rear left, rear right and side right), line out3 does the (centre, subwoofer and side left)
Any more questions, I got my instruction book at hand.
they are only stamped on the backplate what they are
line out1 is green
line out2 is black/grey
line out3 is orange/yellowish