You wish to take a screenshot of your application. You can use PrintScreen then Paste it into the Paint accessory then save the file.
But there's another easy way inside Simulator!
Look at the Tool with the white rectangle around it:
This tool helps you instantly take a screenshot. Thats it!
Just click once and your image file is then created in your destination folder (by default its "My Pictures").
You can display your files using "View saved screenshots", as in:
When you click on it, Windows Explorer will navigate to the destination folder.
You can change the destination folder using "Choose save location..."; it will request a new location from you.
So let's take a look at our screenshot. The screenshots are created using this format : "screenshot_MonthDateYear_HourMinuteSecond"; see: