One 11-man team has possession of the football and is called the offense and it tries to advance the ball down the field-by running with the ball or throwing it to score points by crossing the goal line and getting into an area called the end zone.

The other team (also with 11 players) is called the defense. It tries to stop the offensive team and make it give up possession of the ball. If the football  team with the ball does score or is forced to give up possession, the offensive and defensive teams switch roles (the offensive team goes on defense and the defensive team goes on offense). And so on, back and forth, until all four quarters of the game have been played.

The Field

The football field is 100 yards long and 53 yards wide. Little white markings on the field called yard markers help the players, officials, and the fans keep track of the ball. Probably the most important part of the field is the end zone. It's an additional 10 yards on each end of the field. This is where the points add up! When the offense the team with possession of the ball-gets the ball into the opponent's end zone, they score a touchdown and six points.

Timing

Games are divided into four 15-minute quarters, separated by a 12-minute break at halftime. There are also 2-minute breaks at the end of the first and third quarters as the football teams change ends of the field after every 15 minutes of play. At the end of the first and third quarters, the team with the ball keeps the football heading into the following quarter. After halftime, the second half starts with a kickoff in the same way as the game began in the first quarter.

Each offensive football team has 40 seconds from the end of a given play until they must snap off the football for the start of the next play, elswise they will get a penalty.

The clock stops at the end of incomplete passing plays, when a football  player goes out of bounds, or when a penalty is called. The clock starts again when the ball is re-spotted by an official.

If a football game is tied at the end of the game timewise, a 15-minute overtime period will be played. In the NFL, this is sudden death and the first team to score wins. Possession is determined before the period begins by a coin toss.

The Kick-off

A flip of the coin decides who will start on defense, who kicks off, which endzones each tem will defend.

Every touchdown or fieldgoal begins with the kickoff.

The ball is placed on a one-inch plastic tee 30 yards from the defense's endzone (35 yards in college football). The "placekicker,” a specialized football player makes a short dash to the tee and kicks the ball.  The ball is aimed to wherever would be the worst place for  the offense. Whomever catches the ball on that side is designated the kick returner and will try to advance the ball forward by running.

This is enough to digest for now.