There will not always be teachers to pass their knowledge to you, in a situation where you need to complete a task that is unfamiliar to your knowledge. Self directed learning needs to be put into play here, as there will be no one to help you on the task at hand. As you may or may not know it, you are learning new things everyday and by living life, we are adapting and learning on our own, even without the realization that we are learning. Learning does not necessarily mean only “textbook learning” nor does it mean going onto the internet and pinpointing an answer for yourself. There is much to learn in life that cannot be taught by a teacher in a classroom but that you have to go out into the world and figure out for yourself.
Teaching yourself a new concept can be difficult and might take time, therefor we know how to teach ourselves. Whether it be reasoning, or trial and error, or any other tactic of learning you have in mind, there is always a way to teach something that is even a new idea to yourself.