Just like building a house, when it comes to shaping your body, you’ll want to forge a strong foundation, first. And there’s no better brick than a classic move, to help fortify your muscles and your technique, for any other exercises to come.

Once you master the classics, you’ll be able to mix and match them along with their variations, for better workouts and a stronger you. Here’s how to do a plank.

Let us count the ways. You can do it anywhere, without equipment, and it’s pretty easy to get it right. You’ll also majorly tone your abs, shoulders, arms, glutes, and even your back—creating a strong foundation that not only delivers a leaner look, but helps prevent back pain.

Get on your hands and knees, placing your hands directly beneath your shoulders. Walk your feet back until your legs are straight behind you, about hip-distance apart. Pull your abs in toward your spine and squeeze your glutes for added stability. Hold for 30 seconds. Gradually increase your hold to one minute by adding a second (or five) each time you do the move.

The plank is one of the most versatile moves, because it’s easy to build on, to create more of a challenge—and boost your overall strength. Here’s how:

Even though your forearms create more of a base than your hands, this variation challenges your abs (part of your core) just a bit more.

From the straight-arm plank, bend your elbows and place your forearms on the floor. Fist your hands so that palms face in. Your elbows should be just below your shoulders. Pull your abs up and in to create a straight line with your body, and hold for 30 seconds to one minute.

You can perform this variation from a straight-arm or forearm plank. It challenges your core just a bit more, as you’ll engage it to keep your body still, and the arm release hones in more on your shoulder and upper-back muscles. The bonus? More shoulder and upper-back stability.

From a plank position, release your right hand and extend your arm straight in front of you. Pull your abs in and squeeze your glutes to keep your body still and stable. Hold for 10 to 30 seconds and release. Extend your left arm next and hold; repeat sides for 10 total reps.

Much like the arm extension variation, you can perform this move from a straight-arm or forearm plank. Also like its cousin, you’ll need to squeeze your entire core to keep your body still, so while you’re extending your leg, and engaging your back muscles, you’ll also be tightening your abs—building more overall stability.

From a plank position, release your left leg and lift it three to six inches off the floor, keeping it straight. Lift until you feel your glutes and back muscles engage. Pull your abs in to keep your body still and stable. Hold for 10 to 30 seconds and release. Extend your right leg next and hold; repeat sides for 10 total reps.

Bonus Challenge: Once you’ve mastered the moves above, try extending your arm at the same time as the opposite leg for alternating holds. You’ll create an extremely strong and stable core, and be a plank master in no time.