How to Screen Grab

Taking a photo of your computer screen is called a Screen Grab.
To take a Screen Grab, on an Apple Mac Computer, you have to hold own the three following buttons (AT THE SAME TIME) :

• cmd
• shift
• 4/$ 

When you hold these three buttons down simultaneously, the mouse icon will change to a cross with a small circle in the center. 
When the mouse icon changes to this you hold down the left button on the mouse, drag the mouse to cover the section of the screen you want to take a photo of. 
When you let go, the photo will be taken.