Blank site after child theme upload, can't access admin panel

Hi guys….I need help

I went to upload a child theme for my parent theme. I’m using News Community 3.3 which I’ve downloaded from….somewhere.
Site was working perfect. I had to make some changes in the header.php, so to avoid making changes in the parent theme, I copies all files (except folders) from the parent theme. Zipped it, and uploaded. I’ve done this once already, but with only the style sheet, and something else called single.php.
But now I have a blank site. Nothing loads, and I can’t access my admin panel do reverse anything.
I’ve try to read solutions, but they all say go to FTP server….I have no idea what that is. I installed my site via hostgator.
Can anybody help me recover the site pleaseeee?

site is https://www.cuckoopress.com