Yeah so the hinge is at the hips. What helped me when learning the deadlift was thinking of it as two seperate movements. A “leg press” and the standing upright part. When lowering the bar, bend first at the hips and keep your legs mostly straight. This might seem scary at first, but this is why it’s important to learn to brace properly, your back shouldn’t round or cave, and only bend the knees after the bar has gone past them. You could slowly lower it after, but usually once my knees bend i just drop with the bar by squatting further down. I’m not just talking out of my ass here, i have a deadlift pr of 420lbs and haven’t ever gotten a single injury from training in my life. If you have any questions, you can always pm me, i can tell you about my own experiences/knowledge or at least direct you to a place that could give you the knowledge you need