Stand up with a pair of dumbbells in your hands and at your sides. Your feet should be a bit less than shoulder-width apart. This is your starting position.
With one leg leading, lunge forward and lower yourself all the way down until your front leg is at least at a 90-degree angle. Meanwhile, your back knee will be just a few inches off the ground. While in this position, your back needs to be straight and completely vertical and your hands shouldn't be swinging along back (nor forth) with the dumbbells. Keep the dumbbells tight and fixed at your sides.
Once down, push off with your front leg and raise yourself back up to the starting position. Then, lunge forward with your other leg and repeat the entire movement for the desired or prescribed number of repetitions.
Perform this exercise in a smooth and fluid motion
If you are having balance problems; slow down the movement
Don't allow the dumbbells to tip you over; keep them tight and fixed to your side
SPECIAL NOTES & LEVEL of DIFFICULTY VARIATIONS
To increase the level of difficulty, slow down the movement or use heavier dumbbells.
This exercise looks simple but once you try it you will notice that it's very complex. It involves almost every muscle in your legs which is why the lunge is one of the most effective exercises for the legs.
If you're a beginner you will need some practice in order to get a hang of the mechanics of this movement. Balance is yet another item you will need to master. Thus, doing a few practice repetitions without dumbbells is a good idea.