What does it take to write a kext?

So my laptop's wifi card isn't supported by macOS and I couldn't find any kexts for it. So I was wondering, what does it take to write one?

So the first problem would be: are there any restrictions made by macOS that wouldn't let me use my card, even with a kext?

Second, what resources do you recommend to learn this?

I know it's a hard task, but I'm up to the challenge. Even though I'll likely not going to be able to implement a driver for my wifi card, I'll probably learn a lot. I know C very well, so that's not a problem.