How do I use heat maps to identify abandonment causes?

As a Shopify store owner, I've been struggling with understanding why customers are abandoning their carts. My conversion rates have been frustratingly inconsistent, and I know something is happening on my product and checkout pages that's causing potential customers to slip away. I've tried analyzing my standard Shopify analytics, but they only tell me WHAT is happening, not WHY. I need deeper insights into user behavior—specifically, where people are getting stuck, what elements might be confusing them, and at which precise moments they decide to leave. My gut tells me there are specific design or UX friction points causing these dropoffs, but pinpointing them feels like trying to solve a complex puzzle without all the pieces. I've heard about heat maps as a potential solution, but I'm not entirely sure how to effectively use them to diagnose and fix my conversion issues. I want a systematic approach that helps me understand user interactions, identify potential barriers, and make data-driven improvements to my store's user experience.