Why "done" is used in here? Can I use "do"?
Native speaker’s answer
Rebecca
"How it's done" is an idiom that means "how to do it". Because it is an idiom, it is not grammatically correct, which is why "done" is used. It is acceptable to say "how to do it" instead of "how it's done". Ex: I'll teach you how to ride a bike, let me know you how it's done.