OK, class. Put down those pencils and pens and pick up...your cell phones!

It’s time for Perfesser Mann’s Insta-Guide to Social Media.

You may want to take notes on that phone. Here goes:

—Facebook: “Facebook is for friends and family,” explains my tech-engineer son, adding, “Twitter is for broadcast.” Good, concise summation.

Stephen Colbert had perhaps the best line about Facebook: “Facebook is for connecting with classmates or people you haven’t heard from in years—and 10 minutes later, you never want to hear from again.”

I don’t care much for Facebook, nor does my family. I don’t like a place where people post pictures of their meals or vacays and ask you to “Like” them.

There was a funny sequence the other day in the clever comic strip “Pearls Before Swine.” A guy was hammering away on a piece of granite that was to become his tombstone. His finished epitaph: “Like me on Facebook.”

So why am I on Facebook? Good question: A helpful, useful support group for people who’ve had the same health problem as I.

Other than that, I don’t “Like” Facebook. And it’s not “complicated.”

—Twitter: Please stop rolling your eyeballs, class. I know many of you avoid Twitter because Herr Twittler has sullied it. But I do not follow The Orange Incumbent on Twitter. I let hardier folk do that—those who then make funny or sarcastic ripostes. Those people I follow.

I’ve been on Twitter for over a decade (my son talked me into it). On Twitter, there is no one stopping you from posting/broadcasting virtually anything (i.e., no gatekeepers).

But anything you do post will always remain accessible to all. It’s like a ticking time bomb.

I have a painfully short attention span, so I’m good with reading and posting tweets under the allotted 280 characters. I have 1200 or so “Followers,” (1188 more than Jesus, yuk yuk), about as many as anyone else locally. (One of my faithful followers is Dear Abby, which remains          a mystery.)

I follow only people I deem worthwhile, and especially those who are funny. People like Obama associate David Axelrod, or clever LA Times columnist David Lazarus. And funny people like comics Dana Gould and David Feldman, both of whom I knew in San Francisco. I follow progressive-radio personality and comic Stephanie Miller, and witty Esquire Magazine writer/Trump defamer Charlie Pierce.

But easily the funniest Twitter personality, in my mind, is former GOP strategist and author (“Everything Trump Touches Dies”) Rick Wilson, a regular commentator on MSNBC and CNN. One typical recent Wilson tweet: “In a few minutes at the U.N., Trump will read a speech written by adults. He will grunt and stammer his way through it, hating every second he can’t riff and vamp.”

I often use another social media, live video stream Periscope, to watch Wilson in the green rooms at MSNBC and CNN, answering political online questions in blunt, salty language.

Twitter, alas, is not used by a lot of people here. I do a daily Twitter search for “Port Townsend” and it’s usually posts by local realtors, garage bands coming to town, and tourists’ pictures of pretty PT sunsets and Victorians.

—Instagram: I thought Facebook-owned Instagram was merely a photo site, but I didn’t know this: “I think Instagram is probably the primary way most new restaurants advertise now. Absolutely their food, place settings, and decor are all designed to be “Grammable,” my son explains.

Instagram “is where you post photos of your fantasy life,” he adds knowingly. It’s also where many people try to develop reputations as trendsetters.

“It’s where ‘influencers’ try to present themselves as the beautiful people and get brands/companies to support their fancy lifestyle.” (You can look like Kylie Jenner!) “Some succeed, a lot burn out. There is quite a backlash against influencers now,” my media-savvy son adds.

Instagram is also the medium many young people now use to text, he says. “Messages there disappear after a few hours, just like on Snapchat.”

It’s a whole new world out there, kids.

I feel a bit like the Boomer one comic parodies, complaining: “Why, when I was a boy, we didn’t have MTV. No, we had to take DRUGS—and go to CONCERTS, dammit!”

(PT humorist Bill Mann can be found on Twitter as @Newsmann. Caveat: He uses language there you won’t find in The Leader.)