how can I into philosophy

Are you looking for analytic philosophy or history? Analytic philosophy deals with math, Boolean logic, rhetorical structure. It's a good foundation before you start jumping into books on -isms. Look into some basic thought experiments and try to come up with counterexamples. If you understand basic logical fallacies, syllogisms, and how to deal with contradictions you'll have gotten the gist of how an argument is structured. I should note in philosophy definitive answers are less important than the strength of your argument.

Try https://plato.stanford.edu