Apple Laptop is not sending a ThunderBolt signal to the LG TV


I have my Apple Laptop connected to my LG TV using the Thunderbolt cable that is connected to HDMI input on the TV (purchased cables from Best Buy).   I select the TV source input (both HMDI 3 and HDMI 4) and there is no signal.   It seems the Apple Laptop is not sending a signal to the LG TV.

What am I doing wrong?   Is there a setting on the Apple laptop that I need to set to send a ThunderBolt signal to the TV?    What else should I be doing?   Thanks.   
hgeifman
Thanks for your help. My laptop to my TV connectivity problem is solved. I went into Preferences and clicked on Display. I selected my LG TV and the laptops screen appeared on my LG TV screen. It was very easy and simple. Technology is wonderful when it works.  My issue is closed.   Thanks again.