Set an adjustable bench to an angle of around 30 to 45 degrees and place it in the smith machine.
Before you add the weight, lay on the bench and lower the bar to your chest. Adjust the position of the bench so the bar is lowered to the upper part of your chest.
Grip the bar with a slightly wider than shoulder width grip, and take the weight off the hooks. This is the starting position for the exercise.
Slowly lower the bar down to your chest. (as close as comfortable and you're able to maintain form).
Pause, the raise the bar back up without locking your elbows at the top of the movement.