So basically, I (17M) have a few americans friends in my program, I've realized that most of them are a bit familiar with the stock market cause they would sometimes have discussions stocks or their investment apps.
Recently, two of them (roomates) told me they made a good amount of money from SanDisk and Micron, and they are doing a summer trip with the profits. They have like 10K+ invested at 18\~19, which is just crazy and it just keeps growing since they get support from their parents. I asked one of them his process to find the right stocks, and he vaguely told me that he reads firm reports and follow trend (like AI right now). I think it's a bit of work, gambling and luck, but they've been good so far.
I'm still a bit young to start investing and will also need to get some savings first, but what the best way to start learning about it now so that in a few months, I can start my portfolio and have a good understanding.