When I was in an undergrad, I joined a DNA nanotechnology lab and the assistant professor who was member of the lab gave me bunch of papers to read to get acquainted with the field. When I joined a computational physics lab, it was the same and the professor gave me a paper to read. I do understand that, in labs, you don't have textbooks but bunch of papers to teach yourself.
I am curious about how people in academia self-teach themselves about a field they don't know about. Would they read a review from major peer-reviewed journals, such as Science or Nature, and then dig deeper from there? How would they get teach themselves techniques, and knowledge? When I was in a lab, I didn't have to worry about those things since professors gave me things I needed to read. But, if there was no person like that, how would the researcher get acquainted with the field?