Looking for advice on writing, worldbuilding.

I’m not a native English speaker, so I’m mainly writing for fun (just for myself) and to improve my English. I just started, so I’m really new to this. It is fantasy, historical type.

I’ve got a lot of random ideas, like pieces of dialogue, scenes, characters, families, some ideas for the world, what there will be, territories, monsters, etc. but I don’t know where to start building the actual world.

Do you start to create world with the idea that comes to your mind? Right now, I just save all my random ideas to use later. Is that a bad way to do it?

Also, do you think one can't write without talent, or can write through education?

I’m really into fantasy and historical stuff. Do you research a lot when you write? Like for historical settings, do you look up a bunch of history?

And for fantasy, how do you come up with it? I'm forcing myself to learn about physics, biology, etc. just to create a fantasy.

How do you write action scenes? When I try, I feel like I’m writing too much detail. I even asked ChatGPT once, and it said not to write too much detail.

Just trying to figure things out and would like to hear how other people do it. Could you give me some advices.