Please if any coders can help me with question ?

Please if any coders can help me with question ?

I own a website which I wont mention the link as its not allowed but what my problem is , is that its a traffic and social exchange site I own and run with a licence . I want to know on my main first page URL . How could I place a Image on there like banner size so makes my site stand out using through cpanel file manager as this is a script my site is running from. Should I edit the header.php or the Index.php and where abouts should I place it. I also want facebook button linking to my facebook page and showing the amount of likes . For example : Like our page .

Hope someone can help me and thank you in advance..