The Index
Here you can find almost every guide. If you are starting a new year, follow the guides from top to bottom. This guide will have absolutely everything you need to do to make sure you don't miss anything.
Every document on this site has a unique number that tells you the general category of what the document is about: 1xxx is project setup, 12xx is project structure, etc. The document's number is also how you can access it: a link to /1101 will go to document 1101.
Keep in mind that these guides are extremely opinionated and most people probably won't agree with them.
1000 Project Setup
Here you will find guides on how to start your FTC robotics codebase.
1100 Tools
1200 Project Structure
1300 Libraries
1400 Utilities
2000 Getting Code Running
This is where you can learn the basics of the FTC SDK and get your first OpMode running.