This exercise is also called as flat barbell bench press. This exercise mainly affects the mid chest area. Lie flat on a free weight flat bench press machine. Take a shoulder wight grip and lift the barbell to right above your chest in line to your nipple after adjusting weights according to your capacity. Lower the barbell slowly from the initial position to 3 inch above your chest. Now lift the barbell to its initial position in explosive fashion. Also remember to squeeze your chest while doing this exercise. Having a spotter while doing this exercise is recommended. This is great exercise for strengthening your upper body
Videos Demos on How to do Barbell Bench Press

Video Demo 2