When learning a body of knowledge or a skill you completely don’t know about, you won’t be able to know exactly what you need to learn until you start learning per se, even after conducting an expert interview (use expert interviews to identify best ways to learn a subject or skill).
This is what I experienced with photography. Even after talking with an expert, I wouldn’t be discovering the specific things I need to focus on if I haven’t just started taking photos and using them to complement my writing.
In instances where metalearning does not seem to work before the learning itself, just start learning then apply Josh Kaufman’s advice to identify the minimum viable knowledge you need to acquire before you reach a level where you are comfortable enough to practice ans self-correct.