A question for the grammar geniuses here...

If I wanted to say this sentence:

"If anyone should find out about this, I would be so embarassed... "

"Eсли кто-либо об этом узнает....."
How would I know that the sentence should have "кто-либо" and not "кого-либо" in it?

(and why is it using the the word "-либо" which everyone says sounds "bookish" and not natural?)

I picked up this sentence from a website. I think...