A resource that I would recommend if you're just getting started with bullet journaling is How to Bullet Plan by Rachel Wilkerson Miller. This book contains chapters on everything from the basics of bullet journaling to monthly, weekly, and daily spreads, and even how to make your bullet journal your own. The book also offers tips to get started in bullet journaling, which I found helpful back when I was a complete beginner. The tip that I personally found the most helpful was "Don't overthink it!" because I am one of those people who
overthinks absolutely everything.
There are a couple of things that I really like that Wilkerson Miller did in this book. One of these things is that she shows examples of spreads she has included in her own journal, which makes the book feel more personal, and makes me feel like I know Wilkerson Miller's journaling style better. Another thing she did in her book that I appreciated is that she added practice pages at the very end of the book. I appreciated this because it allowed me to practice basic bullet journaling skills such as calligraphy and other typography aspects without taking up pages in my actual journal.