Have you never studied before, even for school? Alright, the simplest way to describe this to pick a topic of interest, write down key words and words you don't understand down on paper or a program like google docs, read the information and summarize it in your own words and reference the source material. Keep going until you learned everything you have interest in knowing, if you notice some vital information isn't online, you can take free or paid classes regarding it probably, or of course ask here. Make sure to keep your notes organized, but don't be too focused on the design of it itself. The point is to simplify it in a way you can understand, record it and become familiar with every aspect you have interest in knowing. That's about it.