Ok I m new at html n CSS. I have few questions
my site is www.fpshooter.org
I have installed a theme.. so I have php like header, footer, index, etc. and a style.css

1. What file I should edit and what to edit to shift my complete page down so that I can add some banner ??
2. Here you can see I added facebook like button but that button is hidden under the index box. How can I shift it down so that that button would be clearly visible ??
3. If I edit my style.css from my cpanel do I have to do something else to finalize it ?? (other than saving the changes)