What is the Hund's rule for dummies?

Hey there, can someone explain to me in simple terms what exactly is the Hund's rule? I've heard it mentioned a few times in my chemistry classes, but it seems a bit confusing. I'm not really into the technical jargon, so if you could put it in layman's terms, that would be greatly appreciated. I'm just looking for a basic understanding of what this rule is all about and how it applies to atoms and their electrons. Thanks in advance!