I have found from the internet that I need to know these topics for understanding Artificial Intelligence:
Matrix algebra: most machine learning models are represented as matrices and vectors. Concepts like eigenvectors and singular value decomposition appear all over the place.
Bayesian statistics: probability, Bayes' rule, common distributions (e.g., beta, Dirichlet, Gaussian), etc.
Multivariable calculus: most learning techniques use gradients and Hessians at their core to fit parameters. (If you want to get fancier, study numerical optimization.)
Information theory: entropy, KL divergence, etc. Just the basics here.
In limited cases, higher-level math can be useful. E.g., to understand manifold learning, you'll want to know some basic notions from geometry and topology. Occasionally abstract algebra is used (e.g., see "expectation semirings" for learning on hyper-graphs). I would learn these as-needed, but if you have a chance to learn them early it can't hurt.
Now whenever I want to learn these I got confused with symbols, functions, vectors, sets, subsets, etc. Provided I know only the basic math, how can I learn those? I am confused which things should I learn first and which second.
Your question is not an easy one, take my words as a naïve attempt while you catch the attention of someone more enlightened. I can give you a list of books, but if you are an computer science student, the curricula of your university should include some basic courses in linear algebra and calculus, you must start over there, guided tours in mathematics tend to be more successful for the ordinary people. Then you may be ready to basic undergraduate probability and statistics courses. That basic probability course is necessary in order to learn information theory, but mathematical maturity is also really useful.
It's okay to be confused with all those new symbols, you're learning a new language, you should keep that in mind. But most importantly, you must be perseverant, for if you really want to understand the most beautiful and exciting ideas about AI, you must learn to think in more abstract ways. That bunch of symbols is one of the most efficient ways to express these ideas.
Now, if you really insist in trying to do it by yourself:
Also, this book is incredibly useful for computer scientists and mathematicians: