At its heart, American football is simple. Two teams face off, and the one with the most points at the end wins. Points are scored by advancing the ball down the field and into the opponent's designated scoring area, called the end zone.

Each team has two specialized units: an offense, which has possession of the ball and tries to score, and a defense, which tries to stop the other team's offense. They take turns on the field. When one team's offense scores or is forced to give up the ball, its defense comes onto the field, and the other team's offense takes over.

A football game is divided into four 15-minute quarters, separated by a longer break at halftime after the second quarter. While the official game clock is 60 minutes, a typical game lasts about three hours. This is because the clock stops frequently for things like incomplete passes, penalties, or when a player with the ball runs out of bounds.

The offense's main challenge is the down system. When a team gets the ball, they have a series of four chances, called downs, to advance the ball at least 10 yards. The starting point for this is called the line of scrimmage.

If after three downs they haven't gained 10 yards, they face a crucial decision on fourth down. They can try one last time to get the remaining yards, but if they fail, the other team takes possession of the ball right where they are. More often, they will choose to punt the ball, which is a long kick downfield to give the opposing team worse starting field position. If they are close enough to the opponent's goalposts, they might try to kick a field goal instead.

The ultimate goal of any offensive drive is to score points. There are several ways to do this, each worth a different number of points.

A touchdown is the most valuable play, worth 6 points. It's scored when a player carries the ball into the opponent's end zone or catches a pass while in the end zone.

After a touchdown, the scoring team gets a chance to add bonus points in a play called a "try." They can kick an extra point through the goalposts for 1 point. Or, they can attempt a two-point conversion by trying to run or pass the ball into the end zone again from the 2-yard line for 2 points.

A field goal, worth 3 points, is scored by kicking the ball through the opponent's upright goalposts. Teams usually attempt a field goal on fourth down if they are close enough to the end zone but don't want to risk turning the ball over.

A safety, worth 2 points, is a rare but important play scored by the defense. It happens when an offensive player with the ball is tackled in their own end zone. The defensive team gets 2 points, and the offensive team then has to kick the ball to them, giving them possession.

Now that you know the basics of how the game is played and scored, let's test your knowledge.

Understanding these core concepts is the first step to following the action on the field.