The easiest way to take a screenshot is to download lightshot screenshot tool. This is the tool that we use as well: https://app.prntscr.com/en/index.html
If you don't want to download the tool then you need to follow these steps:
Windows 8 and Windows 10
Press Windows Key + Print Screen at the same time to capture the entire screen. This image will automatically be saved to a Screenshot folder inside of the Pictures library.
Сlick the Start button → All Programs → Accessories → Snipping tool. Open the program, click New, select the area of the screen you would like to capture, and then click Save.
Press Shift + Command + 3 at the same time to capture the entire screen and save the picture as a file on the desktop.
You can also download what we in support use called Lightshot. It is a free program for Mac and Windows users: https://app.prntscr.com/en/index.html