There are various ways to take a screenshot / screen dump but the most simplest method is by pressing the Prt Scr button on the keyboard.
The screen dump is saved to your clipboard and you may paste it into any graphic editor like paint for instance.
If in the other hand you were using a MAC, you can do the following:
- Command + Shift + 3: Take a screenshot of the screen, and save it as a file on the desktop.
- Command + Control + Shift + 3: Take a screenshot of the screen and save it to the clipboard.