1. Pitcher mistake: if the pitcher does not pitch the ball into the strike zone and the batter does not swing, then it counts as a ball.
2. If the batter receives four balls before he gets three strikes, then the batter gets a walk. A walk means the batter automatically gets to go to 1st base.
3. If the batter hits the ball out of the field in fair territory, then it's a home run. He gets to run through all the bases and score a run. If he has teammates on any bases, they would score runs as well.
4. If a player is on a base, he can try to run to the next base while the pitcher is pitching. If he reaches the next base without getting tagged, then he has "stolen" the base.