Here in the United States, the World Cup is the one time every four years that the game takes center stage in a crowded sports landscape. The event attracts millions of fans, but those new to the game can get confused, though the sport seems simple on the surface.

For people used to American sports, soccer's pace and rules may seem odd and and even keep them from enjoying the matches.

No worries, we’re here to help.

Any explanation of the rules of soccer must start by looking at the men who call the games, the dreaded referees.

The soccer field is 125 yards by 65 yards and is patrolled by one man with a whistle and two men with flags, both on the sidelines. The man in the middle, the referee, has the power, but his job is not an easy one. His assistants are there to help, occasionally raising their flags for infractions, but the final decision falls on the referee.

While other sports in the American landscape pepper the playing surface with enough officials to invade a small country, the soccer world has resisted temptation and left the human error aspect — officiating — as a major aspect. So, before you start watching games understand this, there will be bad calls, horrible calls, and “Oh my God, did he really just call that?” calls.

Now, for the basics.

No hands, please
Unless you are a goalkeeper, Diego Maradona, or Thierry Henry you are not allowed to touch the ball with your hands or arms unless it’s on a throw-in or to set up a free kick. Seems simple right? Well, like with everything involving soccer there are some catches. A player can be called for handling the ball even if it is kicked into his hand from close range. Then again, that call can also be made as “ball-to-hand” and left as fair play.

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To protect against this you might see a defender standing with his hands behind his back while trying to defend, even if that looks a bit silly.

Consider cards flagrant fouls
After a particularly hard foul it's likely fans will see the ref pull out a card. There are two types, yellow and red, and they have different meanings.

Here’s a simple way to look at it. Cards are like flagrant fouls in the NBA. The yellow card can be considered a flagrant one. It’s a warning to the player that he is on the brink of being ejected. These are generally given for hard fouls, being reckless, talking back to the referee or intentionally touching the ball with ones hand.

If a player is given a second yellow, he will then be shown one of the red cards, and his day is done. But we’re not through yet.

The red card can be given right away. Think of it as a flagrant two, or immediate ejection. These are for violent acts on the pitch. Be it a crunching challenge from behind, an elbow to the face, or in one famous case a forehead to the chest, red cards are usually not very hard to spot. There is one exception. “Denial of a goal-scoring chance” also calls for a red card. Some people refer to this as the “last defender rule.” If the referee judges that a foul was committed to stop a clear chance on goal, he can toss the player who committed the foul.

This is the “tuck rule” of soccer. It’s a judgment call from the ref, and unlike the NFL, soccer doesn’t have instant replay.

Out of play
One common question from American sports fans revolves around why the ball goes out of play and is sometimes thrown in and sometimes kicked in.

It’s where the ball went out of bounds. Corner flags mark the difference between the sidelines and the end lines. If a ball goes out over the sideline it is thrown back into play. 

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If the ball goes out over the end line, it leads to a kick. If the team that is defending nearest goal touched the ball last, it is taken to the corner and put back into play. If the attacking team touched the ball last it is placed on or inside the six-yard box (the little box inside the big box, by the goal) and kicked back into play.

There are a some other notable items. From a corner, the defending team can be no closer than 10 yards to the ball, thus giving plenty of space to get the ball in the air and into the box without having to worry about it being blocked.

From the goal kick, the ball must leave the 18 (that’s the big box) before it can be touched by another player.