How to brew is better especially for all grain. It's more technical...
I did one extract then went to all grain. What I did was pretty much searched the forums for specific questions. I learned the process, so I understood what steps needed to happen. Then I broke those steps down and researched specific questions I had about each process. And I would read several opinions on each question, because sometimes not all processes or techniques are the same. Some are better, some don't matter and some are plain wrong. For example fly vs sparge or no chill methods or brewing in a bag...etc.
While I read, more questions popped up, so I would research those as well and so on.
Start researching the mash process. It'll lead you to questions like temperatures. So then you'll learn why it is important and how it relates to the beers final product. Then that leads to how to maintain those temps. Then it'll lead to efficiency, so you'll learn how to be efficient with your conversion. That'll lead to grain crush, sparging techniques...etc.
Once you have a solid understanding of the processes and techniques,then you can start researching malts, and hops, and yeasts, and all the science behind them. Such as beta and alpha acids. Or the converting process of simple vs complex sugars and how that plays a role in the beer style. Learning about starters and what under pitching does to beer. Also learn about attenuation and flocculation... Etc.
Then you get into water quality and the addition to salts and PH as well as infections... How to diagnose one, how to understand what the infection is doing...etc.
Once I had a good understanding of the process and techniques, then I read how to brew because I felt I understood it more, and my questions were being answered. I felt I retained the info better that way. But each their own.
Don't try to get it all in at once. Just learn the basics first.
Understand the mash and sparge those are really the most important processes during all grain. Make sure you have good temp controlled fermenting too. Then start brewing because you'll learn that it'll take a while to get your gear where you need it and also to fine tune your techniques.
Like you'll miss your mash temp, so you'll research more about how to obtain it and maintain it better. Then you'll upgrade equipment to help. Lol
Good luck.
