This chad just made an entire harem and didn't even try. Those two other guys tried though.
But here's the secret on how to make a harem. Step one: you don't try to get a harem. If you try so hard to acquire one, then you already failed. Instead, don't try to acquire a harem. Be completely normal and antisocial and all the ladies will come swarming in. In other words, the person who tries to get a harem will not succeed; and the person who doesn't try will.