Lie down on an incline bench and make sure your upper chest line is aligned with the cables (the bench should be set up in the middle of the machine apparatus). Grab the handles and spread your arms while bending them slightly at the elbows. This is your starting position.
Raise the weight up until your hands almost touch and then lower the weight back down smoothly until you get back into the starting position. Repeat the movement for the desired number of repetitions.
Perform this exercise in a smooth and fluid motion
Don't let the weight pull your arms back too far down
SPECIAL NOTES & LEVEL of DIFFICULTY VARIATIONS
To increase the level of difficulty, slow down the movement or increase the weight.
The key to this exercise is setting up your bench properly before you start doing this movement. Thus, take a few moments to adjust and re-adjust the position of the bench and even do a few practice repetitions to gauge how good your set up is. Once you set up right you're good to go!
Another point worth mentioning is that this exercise is not for building slabs of muscle onto your chest. This is a shaping exercise which means you don't need to go too heavy with the weights. If you want to build muscle mass you should do barbell or dumbbell exercises for your chest.