For checking the transcript: https://www.buzzsprout.com/2379282
Wrap one’s head around sth
means to understand or comprehend something, especially when it's complicated or challenging.
Examples:
1- Imagine trying to wrap your head around how they filmed those special effects in movies. It’s so cool, but so mind-boggling!
2- When the pop star announced she was taking a break from her career to study astrophysics, fans needed some time to wrap their heads around the surprising news.