Hi
As the Xbox one s does not have a 3.5mm audio output, you will need a HDMI to HDMI + audio adapter like the one linked below. This will use the HDMI port of your Xbox and give you a audio out as well as HDMI.
Good luck
https://www.amazon.de/AAMANKA-HDMI-Audio-Konverter-5-mm-Stereo-HDMI-Notiz-Splitter/dp/B0725KNBMR/ref=mp_s_a_1_10?ie=UTF8&qid=1532577176&sr=8-10-spons&pi=AC_SX236_SY340_QL65&keywords=HDMI+TO+HDMI+%2B+AUDIO&psc=1