Use an overhand grip and grab the bar at the widest points. Your elbows are at about a 90-degree angle when in the upper position. Slightly bend your knees to be in a suspended position on the bar.
From the starting position lift your body up towards the bar while contracting your back muscles and biceps. Go up to a 90 degrees angle at your elbow joints when lifting yourself into the upper position and exhale. The bar is in front of your face in the upper position. Inhale while returning back to elbow extension. Do the required number of repetitions.
Make sure you use the correct grip on the bar. Make sure your torso is firm while exercising. Return to the starting position using a slow, controlled motion and avoid sudden relaxation of your muscle tension.
It is better to begin doing this exercise with assistance from a trainer (partner). The number of repetitions depends on your type of training.