Set your bench to an incline of around 30 degrees. Lie face down onto the bench with your chest sitting at the top point of the bench and your arms hanging fully extended toward the floor.
Take an overhand-grip on a barbell, just outside of shoulder-width. Your core is tight and you use your lower body to stablise you. Depending on your height, you may either pop your feet to the floor and come up onto your toes. Others feel more comfortable having their knees instead up onto the seat rest. This is the starting position.
Commence the movement by pulling the bar up and back, squeezing your shoulder blades together and flaring the elbows out to the sides. Exhale through the movement and keep your torso should stationary. It should not be lifting off the bench. Think of the movement like a "reverse barbell chest press".
Squeeze for a second at the top of the motion and then reverse the movement by extending the arms to the starting position, inhaling as you do.