The non-technical introduction chapter is pretty easy to follow, and I would recommend reading it.
Assuming you have some freshman-college math literacy, here are a few great introductory books to Probability theory:
Introduction To Probability by D. Bertsekas & J. Tsitsiklis
https://www.amazon.com/Introduction-Probability-2nd-Dimitri-... Elementary Probability Theory: With Stochastic Processes and an Introduction to Mathematical Finance by K. L. Chung & F. AitSahlia
https://www.amazon.com/Elementary-Probability-Theory-Introdu... An Introduction to Probability Theory and Its Applications Vol. 1 by W. Feller
https://www.amazon.com/Introduction-Probability-Theory-Appli...I'm sure there are some great video lectures on the subject as well, but unfortunately I can't point you to any relevant material since textbooks is what I used when I was in college. But if I had to guess, the latest MIT OCW material that has video lectures available would be sufficient.
We tend to gloss over assumptions like finite variance or iid but they matter a lot for reasoning correctly on fat tailed distributions.
Also the law of large numbers only works if you don’t have a game over scenario or fat tails.
https://www.amazon.com/gp/aw/review/1544508050/RMD3OUG0WQWWY
Beware that it may be way more advanced than what you'd expect though.