Can’t make heads or tails of it

Can’t make heads or tails of it : não entender algo por ser muito difícil ou complicado

“Before the Olympics, Angelina tried to learn how to speak Chinese. Unfortunately, she couldn’t make heads or tails of it, and she quit after only 3 weeks.”

“I can’t make heads or tails of his teaching style. I can’t understand what he’s talking about.”  (www.idiomeanings.com)