When you're learning a programming language as a beginner, and you're faced with a tutorial (or 10) that feels overwhelming, you must know a few things:
The person who made the tutorial, prepared everything in advance. The video/article is made for educational purposes, not to reflect how real programmers work.
It's perfectly normal to not understand too much. The goal here is for you to type the code, get familiar with the words so when you'll see the same stuff again, your brain will click saying "Hey, I remember this!", and of course, you'll feel proud of yourself! clap clap :)
People were not ready for the tutorials we have here. Our brains can't process the amount of information, their complexity and because there are so many tutorials, we devalue them.
Let's imagine we are 15 years in the past and you'd try to learn programming. You'd get some CDs with a person talking you through code and explaining various concepts. Due to the fact that your resources are limited, you'd devour those CDs making use of every bit of information there. You wouldn't neglect it as you're doing with your udemy courses. Should I even mention freeCodeCamp's 5-10 hours long, free tutorials? -- which brings me to my last point
Commitment. Dedicate yourself to one tutorial, one series or one instructor. It's tempting and often advised to use multiple sources, and to an extent it's a good idea, but serious learning is done through commitment, and commitment means focus.