By WAYNE PARRY | Associated Press

ATLANTIC CITY, N.J. — Sports betting is now legal in 30 states, and more Americans than ever before have an opportunity to place a legal bet on Sunday’s Super Bowl.

With sports betting ads blitzing the airwaves with come-ons and promotions, things might be a bit confusing, especially for first-time bettors or those who don’t fully understand how things work.

Here is a guide to betting on the big game between the Los Angeles Rams and the Cincinnati Bengals. We will deal here only with legal options from sportsbooks approved and regulated by government authorities in the U.S. This includes making bets in person at a casino or racetrack (call before you go; not every casino or track offers sports betting), or setting up an account from a computer or smartphone with online bookmakers.

WHAT IS A POINT SPREAD? OVER/UNDER WHAT?

Two of the most popular bets are on the point spread (the number of points by which a team must win the game in order for the bet to be a winner) and the total, also known as the over/under (the total number of points scored by both teams).

Contrary to popular belief, the point spread is not a consensus on how many points oddsmakers think one team will win by. Rather, it is a number designed to generate as close to an equal number of bets on both sides as possible. That way, the oddsmakers are guaranteed a profit through a cut of the action, called the vigorish, or “vig.” (Many books, hoping to sound less wiseguy-ish, call it “the price.”) Most sports books will keep about 10% of a winning bet before paying you the rest, but they keep 100% of all losing bets. Prices on Super Bowl bets can vary significantly, so it pays to shop around to get the lowest price you can before making a bet.

Beating the spread is known as “covering.” For the Rams to cover their spread of 4 points, they must win the game by 5 or more points. Conversely, underdog Cincinnati can cover by either winning the game outright, or losing by less than 5 points. (Odds and point totals are as of Thursday from FanDuel, the official odds provider for The Associated Press.) If Rams win by precisely 4 points, that’s called a “push” and you get your original bet refunded. This also applies to other bets, which is why most of them involve a fraction, like 44.5 yards or 48.5 points, to avoid a push to the greatest extent possible.

Don’t want to bother with points and just pick the winner? That’s called the money line. A bet on the Rams to just win the game, regardless of the score is an expensive proposition: You will have to bet $198 of your own money just to win $100. (Of course you get your original $198 back as part of the $298 payout.) A money line bet on Cincinnati, however, will win $166 on a $100 bet, for a total payout of $266.

If you believe the game will be a high-scoring affair, you might want to make a bet on the total, currently 48.5 points. That means if you bet the over, both teams combined must score at least 49 points for your bet to win. If it doesn’t, people who bet the under will win.

CAN I MAKE MY OWN ODDS?

Yes. There are alternatives, but they can be costly. Sportsbooks offer so-called teasers in which you can move the line up or down by 6, 6.5, 7 or more points on at least two combined bets. You also can pick your own spread or total to improve your chance of winning, but the farther your pick deviates from the sportsbook’s number, the less it will pay if you win. (You also can choose a harder-to-reach number for a higher potential payout, such as betting that the Rams will win by 20 points, but that’s a very risky strategy.)

A typical teaser bet might be taking the Bengals, who are already getting 4 points, and teasing the spread up to 11, meaning the Rams would now have to win by 12 points. The other half of the teaser could involve lowering the total from 48.5 to 41.5, meaning both teams combined would have to score at least 42 points. The tricky part about this is BOTH bets must win in order for your teaser to be a winner. If your team covers the 11-point spread but both teams only combine for 41 points or less, your bet loses.

WHAT ELSE CAN I BET ON?

If this sounds like a lot to take in, there are much simpler ways to bet on the game, including some aimed at the casual fan or even someone who knows nothing at all about football. A perennial favorite is betting on the coin flip at the start of the game to determine which team can choose to get the ball first. There are only two choices: heads or tails, and it comes before the game even starts for those impatient to know whether their bet is a winner. You can even bet on which color of Gatorade the winning coach will be doused in at the game’s conclusion. Seriously.

This is what’s called a proposition or “prop” bet. It involves betting on whether a particular event will or won’t happen during the game, and there is a vast array to choose from. They can be disarmingly simple, such as guessing which team will get the ball first, whether the first score of the game will be a touchdown or a field goal, and whether or not the game will go into overtime.

Prop bets based on a particular player’s performance are always popular during the Super Bowl. You can bet on whether Rams quarterback Matthew Stafford will pass for over or under 281.5 yards, how many catches his favorite receiver Cooper Kupp will have (over or under 8.5) and how many rushing yards Cam Akers will gain (over or under 64.5).

On the Cincinnati side, you can bet on whether quarterback Joe Burrow will throw for more or less than 276.5 yards, whether he’ll throw more than one touchdown pass and whether running back Joe Mixon will score a rushing touchdown.

CAN I BET WHILE THE GAME IS BEING PLAYED?

People with online sportsbook accounts can bet on ever-changing outcome odds as the game is being played; live-betting is the fastest-growing segment of sports betting. For instance, the game starts with the Rams favored by 4 points, but say Cincinnati scores two quick touchdowns to take a 14-0 lead. The in-game odds will change to reflect the current situation, and you can now bet on whether Cincinnati will win by 14 points, or whether the Rams will lose by less than that. Or say Bengals rookie receiver Ja’Marr Chase is being shut down by Rams defenders, and appears unlikely to eclipse his pregame receiving yards total of 78.5 yards. Bettors can wager on whether he will or won’t eclipse a lower number.

A word of caution, though: The number of these in-game bets and the rapidity with which odds change can be dangerous for those with a gambling problem, and many experts fear they could even tip a casual gambler toward becoming one with a problem. Some good advice: Set a budget in advance of money you can afford to lose, and stick to it. Look at betting on the game as a form of entertainment and not as a way to gain money that you need. If things head south, don’t make additional bets to try to win back what you’ve lost. This is one of the quickest ways gamblers dig themselves a deep hole.

WHAT IF I THINK I MIGHT HAVE A GAMBLING PROBLEM?

Betting on the Super Bowl is supposed to be fun, and for most people, it is. But for others, compulsive gambling is a serious problem. For help, call 800-GAMBLER.