Can i have some help with using the Prt Scr/SysRq button next to the scroll lock!?

Hold up here.. You're trying to save the picture you took with prtScrn button? If you're on windows Paste it into Microsoft Paint. After that, Using the crop tool, crop the part of the picture you want. Then, once you finish cropping it, move the cropped part somewhere and right click and copy, the select new and don't save it. After that, select paste, and the part of the screen that you wanted is there. You can then either chose to save it to your pictures, or to copy it and paste it. Hope this is wht you're looking for! Good luck (: