Using MacBook In Clamshell Mode

I have a MacBook Air I use for certain things. I have been considering getting an external monitor for it. Some of you may be thinking about using a MacBook with an external monitor as well. When you attach the monitor and close the lid on the MacBook, you are in “Clamshell Mode”. There are certain things you have to do to set up “Clamshell Mode”. This article explains how it all works.