Meghan has already mastered this rule. During her first official event with Prince Harry in early December, Meghan reportedly told a couple who asked for a selfie, “We’re not allowed to do selfies.”

Have you ever seen the Duchess of Cambridge all by herself? Like every member of the royal family, Meghan will likely have security with her everywhere she goes.

Save for official signings at royal engagements, members of the royal family are not allowed to sign autographs for the public.The fear is that someone could forge the signature and use it against the family.

Meghan will likely join Harry, Kate, and Will under @KensingtonRoyal on social media. The trio have been providing updates about the charities they support on the account, which has provided an intimate but controlled line of communication between the young royals and the public.

While there is no official protocol against PDA, Meghan and Harry’s predecessors have so far kept things to a minimum. The couple’s engagement photos will probably be the last time we see them get up close and personal.

As per royal protocol, only nails bearing natural colors are allowed at official events.According to nail polish giant Essie, Queen Elizabeth has been a customer of “Ballet Slippers,” a very subtle light shade of pink, since 1989.

While she’ll likely sit with Harry most of the time, entering the room is another story. There’s a procession which begins with Queen Elizabeth, followed by Prince Philip, Prince Charles, Camilla, Prince William, Duchess Kate, and so on.

Again, not an official rule, but it’s often frowned upon when female royals do the cross. Kate can often be found sitting in “the Duchess Slant,” which has her legs slanted to one side. Diana also sat this way.

Supposedly, this is only for when Meghan and The Queen are sleeping at the same house or castle. So if Meghan is spending Christmas in Windsor Castle, she better not sneak off to the land of nod before Her Majesty!

Every year, the royal family celebrates Christmas at Sandringham House at the invitation of Queen Elizabeth. Traditionally, presents are opened on Christmas Eve, followed by church on Christmas morning.

(Text by Hanan Sanusi, Harper’s Bazaar Singapore / Additional reporting by Natalya Molok)