Three core exercises represent the foundations of bodybuilding and power lifting: The Dead-lift, The Bench Press, and The Squat. 

Why are these considered the three core, or essential lifts? These exercises are compound lifts, or lifts that utilize multiple muscle groups. Especially for bodybuilding, exercises will often focus on isolation movements, or movements that focus on just one muscle. Arm exercises like Skull Crushers or Curls are a great example of isolation exercises. Curls really only work the biceps. Skull Crushers, just the triceps. The three core lifts will engage just about all the muscles in your body. Yes, they'll each focus MOSTLY on one muscle group, but you're getting a solid workout for your whole body.

Calling them the CORE lifts is something of good irony, as your core will be one of the hardest workers in each of these exercises. Stability is key when it comes to proper execution in any exercise movement. Doing the movements correctly is very important, as technique is what will build real strength. A lot of the time you'll see people trying to yank up hundreds of pounds on the dead-lift with trashy technique. This is not impressive. Literally anyone could will-power through a lift and just get it off the ground. It takes true dedication to get up to those heavy weights using proper technique. This isn't just good showmanship. Good technique will keep you safe. Not throwing out your back is what will keep you healthy and lifting for decades. Trying to force push way more weight than you can handle will have you out of lifting for good.

 A strong core is responsible for protecting your spine. If you're doing the core lifts improperly, you're gunna hurt yourself. You can get paralyzed, rupture a disk, or enter a coma from destroying your spinal cord. Scary right? Well, it shouldn't be. People do the core lift's every day, you just need to do them right! Sure you're gunna want to look like an IFBB pro, but it'll happen. It's all about patience and dedication. Besides, do it wrong once and you could be out of the game for months, potentially even life. Take it slow, and make sure to really understand the movements. 

Here's a Run Down of the Big 3: 

THE SQUAT

The Squat is undoubtedly the king of all of the compound exercises, so perhaps that makes it the KING of ALL exercises. The Squat primarily works the Quadriceps, Hamstrings, Glutes, Calves, and Lower Back. In order to build big and strong butt and thighs, you've got to be doing squats. This is a the #1 movement for these goals. You'll also be creating stronger bones and tendons from doing squats.

Long Form Version of Squat Benefits, from STRONGLIFTS.COM

Gain Strength. 

Strength is your ability to move your body against an external resistance. The bar is on your back when you Squat and gravity pulls it down. Your muscles must generate force against gravity to control the bar on the way down and Squat it back up. Increase your Squat and you increase the strength of that particular movement. This strength carries over to daily life and sports. Wanna increase your vertical?

Build Muscle.

 Squats work a ton of muscles. Your legs bend, your torso stays tight and your upper-body supports the bar. All these muscles work at the same time to balance and Squat the weight. This releases muscle building hormones like testosterone. The heavier you Squat, the stronger and bigger your muscles become. This delays the loss of lean muscle mass (sarcopenia, 2.5kg/decade over 25y on average).

Burn Fat.

 You lose fat when your body burns more energy than you eat. Your muscles burn energy to lift weight. Squats burn more energy than any other exercise because they work more muscles and with heavier weights. Heavy Squats also increase your metabolism for hours post workout (EPOC). When you combine this with proper nutrition, Squats will help you burn fat and achieve six pack abs.

Your heart is a muscle. Squat strengthen your muscles, including your heart. It makes it more efficient because any activity takes less effort. Walking up stairs or running put less demand on a stronger heart. This decreases your heart rate and blood pressure over time. This in turn increases your cardiovascular fitness. Squatting is good for your heart unlike what some doctors will tell you.

 Squats strengthen your legs. They make you run faster and longer because each step takes less effort. This doesn’t mean you’ll suddenly run a marathon. But a 5k will be easier. Squats won’t make you slow and bulky. You will gain muscle mass when you double your Squat. But you’ll never gain enough to slow you down. Squatting is more like putting a bigger engine in your car.

 Explosiveness is your ability to generate force fast. In physics this is power: how much work you can do in a given time (P=W/t). Stronger legs can do more work in the same amount of time. The more work you can do in the given time, the more power you have. Squats build explosiveness for sports by increasing power. They don’t make you slow for sports, they make you faster.

Gravity pulls the bar down when you Squat. This compresses everything under the bar. Your bones are living tissues (they heal if they break) which react to this vertical compression by getting stronger. Squats don’t stunt growth. They increase the density of your bones. They make them stronger and less likely to break. This protects you against falls and osteoporosis.

HOW TO SQUAT

 Here's a good rundown of how to squat by Layne Norton: 

On to the next one....

THE DEADLIFT

The runner up for king of all lifts is the dead-lift. It's highly contested as to which exercise is the king: Deadlift or Squat. It is not, however, contested amongst any other exercises. The deadlift is perhaps the most utility-oriented lift. There is no other lift that is more representative of real-world strength. Think about moving a couch, or perhaps lifting a bag of mulch. Both actions require a bend over and pick up motion. 

In my personal opinion(me Zach hai!), the deadlift really is the big boss of all lifts. More muscles are worked than any other lift known to humans. Your arms are working hard supporting the weight. Your entire back is bearing the weight, even your upper back which will need to remain rigid in order to keep your shoulders from pulling away from your torso. Your legs are the foundation, so they're working hard too. This exercise will hit your hamstrings and your booty especially hard.

p.s. The idea of this click-bait ass image I found is to show that the leg's should remain straight at all time. This is FALSE. Your legs do need to bend when doing a regular dead-lift. It should be opposite honestly. Your back should NEVER get that bent over. Tisk tisk....

There are two main kinds of Deadlifts: The Stiff-legged Deadlift, and the Bent-legged Deadlift. Stiff leg deadlifts are often called Romanian deadlifts? Why? Not sure, someone go look that up and comment below. The Romanian deadlift is great for isolating your lower back and hamstrings. We'd recommend adding it to leg day for a killer finish to your workout. The Regular deadlift is out focus, as that is the one that's the member of the big three.....

None the less, here's so more info on Romanian Deadlifts:

Core Strength- It is perhaps the safest of the compound lifts. Surely you can fuck up real bad and hurt yourself. We're not saying you can't. What we are saying is that it's pretty hard. The movement is an accentuation of your natural stand-up movement. Your core is working HARD when doing this exercise, so naturally your spine is better protected. Again, we advise using a lot of attention to detail, so don't try pulling more weight than you absolutely know you can do. Over time, certainly up that weight, but at first make sure to really get that movement down. 

How to Deadlift:

1. Walk to the bar. Stand with your mid-foot under the bar. Your shins shouldn’t touch it yet. Put your heels hip-width apart, narrower than on Squats. Point your toes out 15°.
2. Grab the bar. Bend over without bending your legs. Grip the bar narrow, about shoulder-width apart like on the Overhead Press. Your arms must be vertical when looking from the front.
3. Bend your knees. Drop into position by bending your knees until your shins touch the bar. Do NOT let the bar move away from your mid-foot. If it moves, start from scratch with step one.
4. Lift your chest. Straighten your back by raising you chest. Do not change your position – keep the bar over your mid-foot, your shins against the bar, and your hips where they are.
5. Pull. Take a big breath, hold it and stand up with the weight. Keep the bar in contact with your legs while you pull. Don’t shrug or lean back at the top. Lock your hips and knees.

Read more https://stronglifts.com/deadlift/

Yet another GREAT TUTORIAL BY LAYNE NORTON!!!!

Last, and I suppose least.... 

THE BENCHPRESS

Some form of Chest Press is essential to growing your pecs. In my experience, there is no better movement for pecs than a press. Doing all of them is beneficial, as each one will work a different part of your chest. 

The Decline Bench will focus the stress on your lower pectoral. It works more of your chest specifically than any other press. 

The Incline Bench will work your upper chest, as well as much of your shoulder. 

The Flat Bench is what were going to talk about in this section. The flat Bench Press is without question the best exercise for the upper body.

While primarily working your chest and triceps, this compound exercise will test the stability of your core and the support of your entire body. It activates more muscle twitch than any other press. 

Primary Muscles

• The Shoulders will support the bar as the weight is kept from moving past your upper chest. They're also responsible for much of the explosive motion. They share the same amount of the workload with the pectoral. 
• The Triceps are sharing a lot of the workload. They're responsible for executing the lifts, and easing up on the drops. Using your triceps as a vehicle for the weight is ultimately what is allowing the pecs to pinch and squeeze. 
• The Pectorals are squeezing together, creating a tension level which supports the arms in pushing the weight up. As the weight falls, the tension in the pecs causes muscle tearing. This is what is building the muscle. The slower you let big weight fall, the larger your chest is going to grow. 

Secondary Muscles

The Bench Press is a compound lift. It is one of the Top 3 weight lifts because it supports so many muscle groups. 

The core is stabilizing your body while you do this lift. There are three main points of contact when doing the Bench Press: Shoulders, Butt, and Feet. Your legs are working in conjunction with your core to keep your body stabilized. This is your WHOLE core. Your lower back is responsible for much of this stability. 

There is controversy revolving around the arch technique. This is regrading the idea that the back should create something of a bridge between the shoulders and the butt when benching. I used to believe this was bad. I thought that because the torso is not lat agains the bench when doing the exercise there is great potential for injury. While there is some potential for injury, it is not really any more dangerous than a flat back bench. 

Look at this example: 

DO NOT make the mistake of lifting your butt off the Bench.