I think you are trying to connect your smart tv as a full time monitor. If I'm correct, you will need an hdmi cable from the tv to the computer.
However, with windows 10, there is a feature where you can cast to device, which allows you to play a video from the computer to a network enabled device, like your smart tv. For this, you need both the tv and the computer connected to the same home network, but an HDMI cable is NOT needed, as it is streaming over the network and your tv handles the decoding. Then just right click a movie you want to play from your pc and select 'cast to device'.