Hello,
I will speak from my own perspective and how I went about learning stuff in Unreal.
To answer in short, it depends. If you have prior programming or game development experience then it will be easier for you to utilize the documentation. That being said, Unreal is constantly changing and sadly the documentation isn’t always available or very helpful.
I spend my first year in Unreal just tinkering with stuff, following tutorials, when completed I would comment everything out in my own words. This helped me greatly because it forced me to go over the code again and actually think what does each part do, exactly, or what I think it does at the time. That’s when next step came in for me, let’s call it “what if?”. Basically I duplicated the code and started to play around with said duplicate, discovering new nodes, new ways of doing the same thing, hilariously breaking the game, followed by not so fun engine crash.
Eventually I got to the point I could just think of an idea, jump into unreal and start coding without having to look at anything, at least until you hit a wall, that’s when you start utilizing forums/yt tutorials (quick browse)/unreal articles on specific subject and finally documentation, if one if available.
Of course, even after couple years, there are entire systems that I haven’t utilized or simply can’t wrap my head around. Simple fact is, Unreal Engine is such massive tool, it is hard to know all of it, but it does get easier with time.
AI is a great tool, but later on, once you know more you will be able to compose better questions that can hint the right course of action or expose a completely new way of approaching the issue you’re facing. BUT, I wouldn’t rely on AI for learning the basics, it makes so many mistakes (which you are able to filter out with more experience) or will just make stuff up. It’s no joke, if you keep asking about the same thing several times, you will find eventually it will just spit out complete nonsense.
I am not a programmer or had any experience with game making before Unreal.
If you want to learn the basics, there is ridiculous amount of information available on Paid Course sites, YouTube (yeah some are bad, but there are good ones too!), but a good place to start would be going to “Learning” Tab in filtering by view count. Free sample projects are nice too, I did learn a great deal from them.
There are probably a few forum threads here just about that alone.
For your specific needs, like Inventory and Sorting, I am positive you can find how to do all these online. If you have a working inventory already and have a good grasp on how it’s working, then adding sorting shouldn’t be that much of an issue.
Everyone is different and I don’t think there is one universal rule for learning. Someone might be able to read an article once and do it right the first time, others (me) will read it 5 times and still scratch my head. Don’t try to learn everything at once, learn only what you need at the time. There can be multiple ways of achieving the same result, but which one to use comes with a magic of “well, that depends on…”.
In summary
The documentation might not have a ‘how to build inventory’ page. Instead, you look up the building blocks: Arrays, Maps, Structs, UMG widgets, and Blueprint sorting nodes. Docs explain what those tools do, not how to assemble them into gameplay systems. Tutorials teach assembly; docs explain the parts.