Sometimes, I solve a problem without understanding how the solution worked, and I can't prove that it's correct. Is that normal? I don't feel like I understand what I did In The Code

Sometimes i open the tutorial and i understand nothing and i feel like i will be stuck in this problem for the rest of life, what should i do to avoid this?

How can I learn concepts that I don't even know exist?

Is it through trying to solve problems and searching for the solution or should I try to learn all the concepts and keep searching?