Stand up and grab the barbell with your palms up at shoulder-width apart. This is your starting position.
Lift the barbell up until your forearms are almost completely vertical and the bar is just a few inches away from your upper chest (or neck, depending on your size, build and proportions). Then, lower the bar back down but make sure you don't completely extended your arms straight. You should always keep tension in your biceps for maximum effectiveness.
Repeat entire movement for the desired or prescribed number of repetitions.
Perform this exercise in a smooth and fluid motion
Don't extended your arms completely at the bottom
SPECIAL NOTES & LEVEL of DIFFICULTY VARIATIONS
To increase the level of difficulty, slow down the movement or load the bar heavier.