Emulators!?

I found out about such a thing as ZX Emulators
I want to remember my childhood, and it’s just interesting.
I have a couple of emuls here, but I don’t have enough experience with them
Tell me what? how?
How do emulators work?
which one is better?
how to communicate with TR-DOS floppy disks?
which document should I read?
where and what is better to get?
And in general, I’ll listen to any advice.

Thanks in advance to everyone who answers
Best wishes, Alex!

P.S. I apologize if anything is wrong.

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