Do we ever ask you to take a screenshot and you have no idea how?
Here are a few tips:
Windows: Click "Print Screen" and then open MS Paint. Paste screenshot into Paint and save.
Mac: Cmd + Shift + 3 - it will be saved to your desktop
Here's a nice little free program that will let you take a screenshot and do other things like crop it, etc:
Screenshot Captor - Mouser - Software - DonationCoder.com