You find a primary source.
If I want to know "Did Christopher Columbus believe the earth is flat?" I could read modern day articles about it, but I'm going to ignore any that don't include direct quotes from either him or people that knew him. And then I'll double check those quotes to make sure they're authentic.
If I want to know "does more resistance or more volume lead to better muscle growth?" I can find a million fitness blogs about it, but I'll only trust the ones that name specific studies, and even then I'll probably ditch the article and read the study itself.