Trying to create new separate template page???

Im trying to create a new template page and in the code when I call get_header(); it gives me this error
Fatal error: Call to undefined function get_header() in /home/patient/public_html/wp-content/themes/blog_theme/contest.php on line 9

I have had this same problem before about a year ago and can’t remember how to fix it can some help refresh me.

Thanks