How do I learn manual camera settings without getting overwhelmed?

Shooting on auto is not a failure. It got you making images while the manual settings looked like a wall of numbers you could not face. That overwhelm is just the feeling of looking at all the controls at once. Taken one at a time, they are far friendlier than they appear together. Manual photography really rests on three settings that control light and how it looks, and they are learnable one at a time, not all at once. When you try to grasp aperture, shutter, and ISO simultaneously, it is dizzying. When you learn what just one of them does, alone, it becomes simple and even a little fun. You do not have to leave auto behind in a day. You just have to learn one dial. Start with one setting this week. Put your camera in the mode that lets you control only aperture, and shoot the same scene at different values so you see what changes. Learn what that one dial does with your own eyes. Once it clicks, add the next. Manual comes one setting at a time.