Old TV sets just had a co-axial aerial connector - modern sets have multiple input sources - before anything we need to tell the set which particular source we want to use - on my little kitchen set I can choose - TV - SCART - DVD - VGA - HDMI 1 - HDMI 2
Look for a control on the remote or on the set itself that lets you adjust the input source - on my remote the icon is a tiny TV screen pierced with an arrow going into it.
J Baird
October 2014