What the function of PRTSC SYSRQ key (Print Screen) - and How use it?

PrtSc SysRq is one of the keys on the keyboard PC that has a function to take pictures of the active work on the computer screen / PC. This is an example

and

how to use it?
1. Select the object to be photographed / better known by the name of a screen shot
2. Search PrtSc SysRq button on the keyboard. the right of the F12 key
3. To the start menu - accessories - paint
4. in paint, paste the selected object
5. to cut an object, click crop and then cut
6. paste the object in the blog, wordpress, MS.Word, etc.

Please try it at your home ^^