If you're pressed for time and want the basics of the field, here is short summary of the next few tutorials:
The Infield and Outfield
The foul lines are kind of like inbounds and out of bounds in baseball. If a batter hits a ball outside the foul lines before the ball passes first base, it's a foul ball. If the ball stays on or within the foul lines it is a fair ball.
Other Lines And Shapes
The on-deck circle and dugout are where the batters and other players on the team wait their turn to bat when their team is on offense. There's a mound of dirt at the center of the infield called the pitcher's mound. It is used by the pitcher to throw pitches to batters at home plate.
There are three boxes on the field called the batter's box, coaches' boxes, and catcher's box. These boxes are used for various aspects of a baseball game and are focused around hitting, base running, and coaching.