Simple terms:
Setup the camera angle in the Film Viewer the way you want the screen shot to appear. Next go to "Full Screen" mode. Now press the, "Prt Scr" button located next to, "Scroll Lock."
Now go to: Start>Programs>Accessories>Paint. Press Ctrl + V or go to: Edit>Paste.
Edit the image (If necessary) then save it to a location easy to find it. At this point it is preferred that you convert it to .jpg using a converter such as IRFanView. Paint can save it as .JPG, but it doesn't compress the file as well as IRFanView or Photoshop.
After you convert it to .JPG you can use a website such as
http://www.imageshack.us to host your image, then you simply paste the image inside the [ img] [/ img] tags and you should be good to go.