The clock is ticking. We haven’t got much time. I put down the crossbow and run. The guy next to me is stitching up a wound as fast as he can. “Hurry up!” a voice nearby screams. “The zombies are coming! Oh my God! We’re all gonna die!”

It’s just a regular sunny Saturday afternoon at the Zombie Survival Course, held at a deer-hunting range in south Jersey, where I’ve come to convene with fellow doomsday-obsessed nerds and prepare for World War Z.

In our first workshop of the day, black-clad instructor Mark Scelza quizzes my group of five on some essentials. “Who can tell me, what’s the hardest thing about a zombie apocalypse?” he asks.

“Finding shelter?” one guy ventures. “Food?” asks another. Our instructor shakes his head.

“The hardest thing about a zombie apocalypse,” says Scelza, “is pretending you’re not excited it happened!”

So true. Otherwise, why would any of the 19 of us be here? Morning introductions over coffee and doughnuts mostly revolve around swapping favorite zombie movies or shows. Needless to say, there’s a big “Walking Dead” contingent among us, but there are also classicists (the original “Dawn of the Dead”) and fast-zombie fans (“28 Days Later”).

Of course, the handy thing about gearing up for a zombie attack is it’s remarkably similar to learning how to weather any other type of large-scale disaster.

Hence, today’s classes, rotating among our four small groups, will cover what to pack in your preparedness “bug-out bag” — the same as most disaster kits, power bars, water, matches, knife — simple medical procedures like administering injections, applying tourniquets and stitching up a wound; hot-wiring a car (ahem, “acquiring transportation”); learning to shoot various firearms; and defending yourself in hand-to-hand combat, be it against the living or the undead.

My jovial, mostly male fellow recruits, who hail from Jersey, New York and Pennsylvania, include some sons and dads (best Father’s Day present ever!), one young couple (she’s a paintball dynamo) and a pair of wisecracking city slickers sporting death’s-head handkerchiefs around their necks.

Our instructors, who’ve been running this course for three years, are NRA-certified Scelza, 48, and his crossbow-packin’ wife, Sue, also 48; Jonas Sherman, a strapping and sardonic 36-year-old martial-arts specialist; and “Reverend” Ed Donley, 46, a white-haired ex-military chap who can make an electrical fuse out of a gum wrapper. These are the people you want to be around when the dead rise and wander the earth.

I, on the other hand, estimate my skills level at “zombie bait.” So I am shocked to find I’m actually not half bad with a crossbow. The highlight of my day, in fact, will be when one of my teammates asks me if I’m a ringer. (Those repeated viewings of “The Hunger Games” are clearly paying off.)

The crossbow — a favorable end-of-days weapon, because you can make your own arrows in a pinch — is heavy and intimidating. Sue introduces us to it by showing us a photo of somebody’s hand with the thumb sliced clean off, which is what happens if you have it in front of the cables when you pull the trigger. Lesson internalized, disgustingly but effectively.

Equally graphic is the sutures demonstration, courtesy of Sherman, who reaches into a cooler and slaps a gashed pig’s foot in front of each of us, then shows us how to neatly sew up the wound with a surgical needle and thread.

He also teaches us about “melee weapons,” which (I didn’t know, soft and helpless Brooklynite that I am) are the ones that don’t shoot. There’s a table of them on display here, from tiny knives to giant axes. They do different things: chop, slice, smash.

“If you’re chopping,” Sherman points out, “there’s going to be a lot of blood. With zombies, that’s going to turn you” into a zombie yourself. Duly noted: Avoid chopping when mixing it up with the undead.

Smashing is good, though. So he hands each of us a (padded) stick and teaches us some basic “zombitsu” moves, like slashing down from your right shoulder to your left hip. Then, we’re divided into two groups: I’m with the zombies, facing off against the humans.

“Zombies, are you ready?” Sherman shouts. “Brains!” we reply, and start stumbling across the field, arms out, easily dispatched by the cushy blows dealt by our still-living adversaries. If only real zombies were this accommodating.

But the most definitive — and satisfying, let’s be honest — way to kill a zombie is with a shotgun. So we spend the majority of our afternoon learning to shoot (with a break for ice cream in the middle, unlikely to occur during an undead uprising but awesome nonetheless).

We each get a chance to fire every weapon: from an old-timey revolver to a huge, modern black shotgun that’s as loud as a firework going off next to your head. Luckily, we’re all sporting industrial-grade ear protection, but everyone still flinches the first time it’s fired.

I surprise myself by actually hitting my target (with real bullets) a bunch of times. But the last rifle I use slams against my shoulder when I fire. Aching, I opt out of my last shot.

“Are you going to do that in the real zombie apocalypse?” chides my teammate, Bret Badger. He’s got a point. I’d better toughen up.

I rally for the last event, the skills relay in which we’re tested on everything we’ve learned — except now we’re being timed, and under duress. Each of us is picked for our sharpest skill. I get to pop balloons with the crossbow. Rob Lewis, our stitches expert, sews up a now-ripe pig’s foot in record time, while Sherman and the Scelzas’ son, Sam, take turns screaming at us to increase the stress.

We take out zombie targets with a paintball gun, Bret distance-shoots a can of shaving cream with a rifle, his brother Jack hot-wires an old red truck, and we’re done.

My team wins the relay, and I drive away that evening feeling my skills level has been upgraded from bait to, at least, “fighting chance.”

Zombie Survival Course offers day ($179) and weekend-long ($450) classes. Sessions open to the public are over for this year, but you can pre-register for spring 2013 on its site at zombiesurvivalcourse.com — and it can be hired for private or corporate events.

You can also catch the crew at New York Comic Con on Oct. 13, where they’ll be hosting the panel “Can You Survive a Zombie Apocalypse?”

Other ways to get your zombie fix: Check out the New Jersey Zombie Walk on Oct. 6, more info at njzombiewalk.com. And AMC’s “The Walking Dead” returns Oct. 14.

sstewart@nypost.com