Saving a screenshot on a Windows PC is easy. Just hit the Print Screen key, then paste the image into a document or email (more details here).
However, if you use a Mac, you have to learn a different shortcut combination.
In fact, Macs have a number of different functions built-in if you want to save a screenshot. Here are two of the main options.
If you want to save an image of everything you can see on your screen, hold down the Command and Shift keys, then tap the number 3. This will save an image of your entire screen to your Mac's desktop, with a filename starting Screen Shot. You can open and edit this in normal graphics software.
Alternatively, press Command, Shift, Control and 3 to copy the image to your Mac's clipboard. You can then use the Paste option (Command-V) to paste this image into an email or document.
If you don't want to save an image of your whole screen, try Command, Shift and 4. This will turn your mouse pointer into a cross-hair. Click and hold the mouse to draw round the area you want to save. When you release the mouse button, the area you selected will be saved to the desktop.
Similarly, you can use Command, Shift, Control and 4 to copy the selected part of the screen to the clipboard. Easy!