Then how does it work? Enlighten me.

He bought Twitter because he wanted to pump the stock up, presumably so that he could dump his stock. The timeline is that Elon talked about taking Twitter private, paying 420$ per share, because 420 is the funny marijuana number. Twitter’s board then agreed to the buyout, since Elon’s offer was far more than what the company was actually worth. Elon tried to weasel out of the deal, but Twitter successfully sued him to force him into buying Twitter.