I want to learn more about the Bogleheads investment philosophy. How do I get started?

I’m new to investing and interested in learning about the Bogleheads investment philosophy. Initially, I planned to follow the "Three-Fund Portfolio" strategy to generate passive income through dividends. However, after speaking with more experienced investors, I realized this approach might not be as feasible or practical as I originally thought.

I’ve also come to understand that investing involves more than just buying index funds, ETFs, and stocks and then leaving it at that. With this in mind, I want to deepen my knowledge so I can make more informed decisions in the future. I’m considering taking a university course or reading books on investing but feel unsure about where to start.

Could anyone recommend resources for learning about the Bogleheads investment philosophy and how to apply its principles to my investment strategy?