Here are my confusions and what often makes me change my learning material.
1) Is it up to date or not? (What should I filter in the relevant course, <5 years?) Science, engineering.
2) Is this course suitable for me or not? For example, if I'm a high school student, is it appropriate for me as a complete beginner?
3) There are many study materials available, so how can I decide which one to choose? For instance, recently I wanted to learn about aircraft, but I wasn't sure what topics I should study or how deep I should go. I came across materials on aerodynamics and found many courses on YouTube, MIT OpenCourseWare, and others.
4) What type of material should I look for? (Books, lecture videos, Wikipedia, lecture slides, handwritten notes, or something else?) #inspiration source