Record your computer screen
If you have Mac OSX Lion (10.8) installed* you can easily make your own screencast (a video of what’s happening on your computer screen). This can be helpful if you need to demonstrate how to do something or illustrate a problem you are having to someone who isn’t with you.
Open up Quicktime Player (in Applications), go to File > New Screen Recording and then click the red Record button when you’re ready. If you click on the arrow button you can choose a microphone for audio input as well.
*If you don’t know the version of operating system (OS) you’re running, click on the apple icon in the top left corner of your screen and choose About This Mac. The OS/Version number is right above the Software Update button.