I will try to help you with this question.
You can use both inputs,The coax input is a digital input and the red/white one is analog.
You will get the better quality if you are using a coax digital cable from the coax digital out on the tv to the coax digital input on the Bose.
The cable you need can be bought here:
This is the best price I could find.
If you decide to use the red/white analog input,then you have to run this dual cable from the tv audio out(red and white also) to these red and white inputs on the Bose.
You may find these cables at any retailer like Best Buy or even Walmart,but,please do NOT fall for the salesmen push toward an expensive-Monster type cables,they are a lot more expensive and do not bring anything to the quality of the sound!
What you need to do is also to enable the TV external speakers in the TV menu.Based on the model#,Samsungs have a feature to enable the external or internal speakers.
I hope this helps,
Thank you and Happy Holidays