A book that explains how learning works

I feel very uncomfortable while learning a skill and I am curious how much struggling is normal and how hard is actually learning is. How the process works exactly that I can feel normal and confident when I come across to setbacks while studying a topic or learning a new skill? If I have more knowledge about the process itself, it might help me and encourage to continue without avoiding it by anxiety.

Anyone knows a book that explains this? It can be scientific or self-improvement type, doesn’t really matter. Just simply explained would be easier for a non-scientist person to understand.