Live: The Royal Wedding of Meghan Markle and Prince Harry

Right now: Royal watchers in Britain and around the world are getting ready for the big event.

Good morning from London, where The New York Times Royal Wedding Team is on full alert.

• At noon (7 a.m. Eastern), Prince Harry, 33, the grandson of Queen Elizabeth II, will marry Meghan Markle, 36, an American actress, at St. George’s Chapel at Windsor Castle, which is (you might have guessed) in Windsor, an ancient town near Heathrow Airport.

• The prewedding period has had more than the usual complement of unforeseen mishaps, but all appears to be well now. Ms. Markle will drive to the church with her mother, Doria Ragland, and walk down the aisle with her future father-in-law, Prince Charles.

• In the scheme of things, this particular marriage is not really that important. Harry is only sixth in line to the throne. But Ms. Markle is a highly unusual royal bride: She’s American, three years older than Harry, has a high-profile career and is biracial.

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All of this excitement might tire you out, especially if you’re in the United States, where it’s still the middle of the night. So pace yourself. Make a big pot of coffee.

Here’s what to expect.

At 9 a.m. in Britain, more than 2,000 members of the public who have been invited to watch the wedding party enter and leave St. George’s Chapel will begin congregating on the grounds of Windsor Castle.

As they have many hours of congregating to look forward to, they’ve been advised to bring their own lunch.

At 9:30 a.m., guests start entering the chapel. The guest list hasn’t been released, but expect a healthy mixture of British and foreign royalty; lots of royal relatives, some of whom you’ve heard of, others you haven’t; friends of the couple; friends of the royal family, and important figures who should be invited to these sorts of things.

The couple have ruled out inviting politicians. That avoids the potential unpleasantness that might have ensued had they invited Barack and Michelle Obama, who are their friends, but not President Trump, who is not the most popular person in Britain.

At 11:20 a.m., members of the royal family start arriving.

At 11:45 a.m., Harry gets to the church with Prince William, his best man.

At 11:55 a.m. Queen Elizabeth arrives.

At 11:59 Meghan arrives in a car with her mother, leaves the car and enters the church. Everyone gets to see her dress, decide whether or not they like it, and speculate how much it cost. Prince Charles will escort her to the altar.

The service will last an hour, after which Meghan and Harry will take a little jaunt in a carriage through the streets of Windsor, where they and the crowds can wave at each other.

You probably have a few questions about the royal wedding, having never married into royalty yourself.

Who is going? Why? Do the bride and groom get to bring their corgis (do they have any corgis)? Why is the royal family so fixated on corgis, anyway? Will the guests be subjected to that perverse and baffling British tradition, the serving of wedding fruitcake?

Which of many possible military uniforms will Harry wear to the ceremony, and how did he decide? What’s the deal with all these hats that are actually called fascinators and are not, strictly speaking, hats at all?

We’ve answered over 100 questions to help you understand these and many more of the day’s pressing issues. (It’s a pretty exhaustive list and contains even things you didn’t realize you wanted to know.)

And, for anyone who remembers the electrifying moment that Pippa Middleton sashayed into the church in a slinkily form-fitting bridesmaid’s dress at her sister Kate’s marriage to Prince William in 2011, there is another matter.

Who will be this year’s Pippa? And what aspect of her (or his) outfit and physique will seize the public imagination this time? Is it possible to improve on the nickname instantly awarded to Pippa: “Her Royal Hotness”?

Ms. Markle has had a lot to contend with since she and Harry announced their engagement in November.

Their whirlwind courtship began with a blind date, segued to a romantic camping trip in Botswana and ended with a proposal as the two were at home, roasting a chicken.

England can be a tough place for an American, especially someone who comes from California and is not used to year-round damp and a chronic lack of light.

Her new home is a beautiful apartment in an actual royal building — we’re talking about Kensington Palace, which is definitely something to write home about.

But the palace, it must be said, is also full of members of Harry’s extended family. Would you want to live surrounded by your in-laws?

The worst part for Ms. Markle has been the media scrutiny.

The notoriously sharp-elbowed British tabloids exhausted the usual topics about Meghan herself — her appearance, her career, her wardrobe, her past romantic history, her class status, her forthright manner, whether she or Harry had the upper hand in the relationship, her circle of friends, the fact that one of her earliest acting jobs, on a game show called “Deal or No Deal,” required her to wear a minidress and hold up a silver briefcase stuffed with money.

Then they turned their attention to her family.

We all have relatives who, if we got married, we pray fervently would do us the favor of staying home, keeping quiet and refraining from publicly announcing how insulted they are by our failure to invite them to the wedding.

No such luck for Meghan.

Egged on by silver-tongued reporters wielding piles of cash, some members of her family that she is not in touch with, such as her half brother and her half sister, have attacked her in the news media.

Meanwhile, her father, a former Hollywood lighting director who retired quietly to Mexico, made a rookie error, apparently posing for a group of photographs that were then falsely marketed as having been taken without his permission. Having set the trap, the tabloids savaged him for falling into it.

Humiliated and confused by forces no one had prepared him for, Mr. Markle had heart surgery last week and the palace announced that he would not be coming to his daughter’s wedding.

As for Harry, Meghan seems to have brought him happiness and a sense of maturity and calmness.

As the younger of Prince Charles’s two sons, freed from the burden of being a future king, Harry seemed to charm and party his way through his youth.

He dated a string of (mostly blonde, mostly aristocratic) young women, always looking as if he were psyched to stay up later and celebrate longer than anyone else.

He made some missteps. As a teenager, Harry once wore a Nazi costume to a costume party. In 2012, he was photographed partying, and possibly playing strip billiards, with a young woman and her friends at a hotel in Las Vegas.

But being in the army — he served twice in Afghanistan — gave him a sense of purpose, discipline and camaraderie.

Now he is the patron of many charities, particularly ones helping injured and disabled military veterans. In 2014, he started Invictus Games, a Paralympics-style athletic contest for injured former service members.

He was only 12 when his mother, Diana, the Princess of Wales, died. It’s hard to forget the haunting sight of him and William, wearing their grown-up suits, walking behind their mother’s funeral cortege.

Harry, who has spoken about how bereft he felt and how he finally sought counseling to deal with his grief, has said that he thinks Diana would have loved Meghan.

“They’d be thick as thieves, without question,” he said after his engagement was announced. Of Diana, he added, “And she would be over the moon, jumping up and down, so excited for me.”

Even if you happen to be in England on Saturday, don’t make the mistake of thinking you can just hop on a train and head out to Windsor at the last minute.

First of all, you might not get a seat. And when you do arrive in Windsor this morning, it’s going to be extremely crowded.

You will have to contend with the keen royal-watchers who, having arrived in some cases days earlier, have already snagged all the good spots along the royal route.

That’s in addition to the thousands of police officers, some on horses, with their sniffer dogs, their metal fencing, their vehicle recognition technology, their closed-circuit TV cameras, their helicopters and their marine patrols of the river.

Don’t think that you or your drone can fly over Windsor, either; the police have designated it an exclusion zone for low-flying traffic on Saturday.

Perhaps 100,000 people will crowd into the little town today. No one is saying how much the security operation will cost, but the current (unconfirmed) estimate is that it will come to as much as 30 million pounds.

That’s about $40 million, with the bill to be paid by British taxpayers.