Korean

I just stumbled upon this extension and am trying to use it. But my wife, who is Korean, says that the dictionary that is used to translate is not entirely accurate. We tried 3 different TV shows. I tried to add a dictionary in Settings in the user dictionary area but I’m not sure what I’m doing wrong. The website is https://papago.naver.com/

Also, it this is added correctly, would it translate what the video is saying or only show if you click the English word?

Thank you in advance.