After that set the TV as a second screen and set the video resolution to match the native resolution of the TV.
Some video drivers give you more options to adjust so you can optimize the TV without changing any setting for the laptop display.
It may also require a bit of messing around to get the TV and laptop to "handshake". Sometimes you have to boot the laptop after selecting the HDMI input you connected it to. Might take 10 seconds to get a picture. The cable you use can also affect this.