Major League Soccer is officially in Atlanta.

Atlanta United FC, an MLS expansion team, plays their inaugural game on Sunday at Bobby Dodd Stadium. The game is sold out, and the team has sold more than 30,000 season tickets.

Want to join in all the fun? Before you do, you should brush up on a few basic facts about MLS and soccer:

  • MLS is the top professional soccer league in the U.S. and Canada
  • There are 22 teams in the league (19 in the U.S., three in Canada), and they are divided into an eastern and western conference
  • The MLS season runs from March to October
  • The game is simple: 11 players on each team try to score more goals than the opponent. Players can only use their feet, except for when throwing the ball in bounds. If the ball does touch a player's hand, it's a handball and a loss of possession
  • Goalkeepers, who defend the goal, are allowed to use their hands when inside the penalty box and to block shots
  • A player with possession of the ball cannot pass the ball to a teammate who is beyond the opponent's defense, or offsides. If an offsides occurs, it is a loss of possession
  • Each team is only allowed three substitutions per game
  • If a player commits a foul that was overly aggressive, a referee can issue a yellow card. If a player gets two yellow cards in the same game, he is ejected from the match and is suspended from the next game. If a player is issued a red card, the consequences are similar to getting two yellow cards. Red cards are given for a serious, dangerous foul or a complete lack of sportsmanship
  • Players who are ejected cannot be replaced by substitutions, and therefore cause the team to have less men on the field
  • If a foul is committed against a team, that team gets to take a free kick to start a possession. If the penalty happened inside the box, the team gets to take a shot on goal
  • Soccer consists of two 45-minute halves
  • The clock counts up to 45 in the first half. Then, it continues in the second half until it reaches 90.
  • After each half, there are minutes added to make up for lost time through substitutions, injury, wasting time, etc. The referee uses his or her discretion to decide how much time is added, and the added time is announced on the sideline. It is referred to as injury time or stoppage time
  • The clock does not continue to run during stoppage time. The referee keeps the time on the field
  • The equivalent of overtime in MLS is called extra time. However, there is no extra time during the regular season. So even if a game is tied after 90 minutes, or there are no goals scored, it ends in a draw
  • The MLS postseason is called the MLS Cup Playoffs. There are 12 teams that play in the playoff. They are the top six from each conference
  • The winner of the MLS Cup final wins the MLS Cup. The Supporters' Shield is an annual award given to the team with the best regular season record
  • MLS is part of the CONCACAF confederation and FIFA is the sport's governing body
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