Add aux jack to Becker BE1350

Does anyone know how to add aux jack to Becker BE1350? or have schematic of it?
Thanks
you open your stereo to gain access to the green board then identify 3 dots with L R N. Solder your AUX three wires to them. But you have to play Empty tape or (empty cd if connect to cd board).
there are many vids on youtube.



