Basically it starts with your interest with this matter in this type of industry and everything i knew, i got it from this forum and from google searches and also by my friends that I know. It wouldn't hurt to have a basic knowledge of economics, which was thought in school days but basically the rest would be just reading posts, common sense and a heck of a lot of google searches or youtube vlogs and reviews.
We are all starting right there reading some small information and then we dig and dig more as is the information is getting interested, while the school doesn't really teach you everything that's why we have to do it in our own way. We are so lucky today because we could just easily search everything now on the internet.
That is the way we all begin our journey, very few can get to know everything about this market from the beginning, it takes months of effort just to get to a comfortable level of knowledge and even after that you realize that your knowledge is not enough to make money in the markets, so the best thing to do after you learn a new set of skills in the market is to try them out so you can get some experience about what works in the market and what does not work.