The verb "narau" does mean to learn but it has to be in reference to learning something FROM SOMEONE, so you would have to say something like: 友達にカップケーキの作り方を習いました。 Tomodachi ni cupcake no tsukurikata o naraimashita. I learned how to make cupcakes from my friend. It doesn't have to be a formal learning/teaching experience but "narau" cannot be done alone. It also makes the sentence unnecessary long when talking about an obvious learning subject, so it is not often use.