The most important concept to understand is
https://en.wikipedia.org/wiki/Kelly_criterion
That is, you make money trading if you have a predictive model and use Kelly to turn that into bets.
See this book
https://www.amazon.com/Dr-Beat-Racetrack-William-Ziemba/dp/1...
for a strategy that still works and an example of "predictive model + Kelly". (e.g. that strategy still works because anybody who masters it and would scale it up goes on to Wall Street and plays for bigger stakes)