creating a custom, responsive header

I was hoping my theme would have a way for me to edit the content in .site-header-area but it wont so I am trying to create a new header.

I’ve created a header-blog.php file already. My question is what code should I use to create this header for a specific page? Do I have to override the header.php code with the new code? How do I make sure this header only displays on one page? (I want a little blurb of information on my blog page, with an image, hence creating a header for that page only.)

Thanks for your help