I would love to read a well written book on a subject - provided that I have the time. But sometimes we do not need to become experts on a particular field but still need the basics. For example, a question in my research is related to Lie algebra, which I know very little about, thus I would like to learn the basics of Lie algebra. However, I do not have say $300$ hours to read a text book such as GTM $9$ (Introduction to Lie Algebras and Representation Theory, James E. Humphreys) in detail.
Let's say that I can spend $30$ hours on this subject and would like to learn the basics, can anyone recommend some materials/methods? Currently I am watching a youtube playlist on Lie algebras and their representations but I am not sure if it is the best way to "quickly" learn the basics of the subject.