Check the ports on your MacBook and monitor
Get the correct cable or adapter
Connect the MacBook to the monitor
Turn on the monitor
Select the correct input source on the monitor
Open System Settings on your MacBook
Go to Displays
Arrange the displays if using multiple screens
Choose mirror or extend display mode
Adjust resolution and refresh rate if needed
Close the MacBook lid if using clamshell mode
Connect power, keyboard, and mouse before closing the lid