How to learn/ to find the textbook to help you more understand the thing you’re learning

I spend a lot time to do my homework, and I’m care about my grade but I’m more care about “ am I really learn the thing we talking about in the class?” I hope you can understand what am I saying, Im really just finished my homework but im not really learn any knowledge from there😭😭😭 I’m so anxious about that, I hope van get some advice to improve my learning skills