Just set the amount of enemies, the speed, and enjoy. You can sit and watch the ai's train or grab a snack or something, or maybe just go afk.

Farmer Joe will follow your mouse wherever it goes. If you get close to one of the cows, it moves away from Farmer Joe. So you can steer your cows into the gate at the bottom right. However if you end up touching the cow, the cow gets scare...