Make sure your Mac and TV are on the same Wi-Fi network
On your Mac, click the Control Center icon in the menu bar
Click Screen Mirroring
Select your TV from the list
Enter the AirPlay code on your Mac if prompted
To stop mirroring, open Control Center again and click Screen Mirroring
Select Stop Mirroring
If your TV supports AirPlay, use AirPlay directly from the Mac
If your TV does not support AirPlay, connect an Apple TV to the TV
If needed, use an HDMI cable and adapter from your Mac to the TV
On the TV, switch to the correct input source if using HDMI
On your Mac, open System Settings
Go to Displays
Choose Mirror or Extend Display if available
Adjust display settings as needed