Survey the landscape first - get a hand-wavey high level understanding on the two primary schools today: analytic vs continental philosophy. Then study each one’s history and origins.
Read this book (also available as YouTube videos I think): https://www.amazon.com/Philosophy-Book-Ideas-Simply-Explaine...
This will give you high level introduction of the landscape across the various epochs, the big ideas and their main purveyors.
At the end of that you should have a good idea which philosopher/era/ideas interest you most. Only then consider diving deeper.
Specifically because you speak of mental models and “developing a personal philosophy” (and because you are on this website I am making some assumptions about your background ans familiarity with computer science/information theory) I also recommend Luciano Floridi. The Logic of Information: A Theory of Philosophy as Conceptual Design
https://www.amazon.com/Logic-Information-Theory-Philosophy-C...