The batter straddles the box and tries to slap the ball into the pitcher's box, hoping it would not be caught. Some guys can put so much spin on a ball that, unless you had arms like Wilt Chamberlain, there's no way you can hit it. You can edge up and straddle the box as close as you can, hoping that by leaning in you'll get a piece of the ball. After the swing, you have to make sure to keep all body parts out of the box or else you're out. Good balance and the ability to stretch are some of the subtleties to this game.
Bigger boxes are advantageous to the pitcher's skills.