How can i use another main line outputs in stereo

Hi Lazio,
Thank you very much for your answer and reply i got it player from USB storage device in stereo mode yet. Yes i using unbalanced connection from Lp 16 and compare to all outputs i found just 1st output only it’s very thin and smaller sound like low cut to 250 Hz ..i would like to change output how to open in audio interface mode play multi media like i tune , youtube ete..
thank you very much,
taosabai