If you really want to learn about normalization of databases, then go to the web and try "Database Normalization" for a search. You have to include the word "Database" since by itself, "Normalization" is used in databases, politics, chemistry, math, and social science - and maybe a few more beyond that.
You will get a pot-load of articles. (You get to guess what kind of pot.) For starters, look at articles from .EDU sites - colleges and universities - since they will be less likely to try to sell you something. Once you have a bit more confidence in what you have read, return to the .COM sites for more articles. Eventually you will be comfortable with the subject and will recognize that the .COM sites are sometimes trying to sell you something but also have some nuggets of wisdom for you.