Grasp both of the handles while in a standing position. Once you have a firm grip, bend over until your upper body is at 45 degrees (in relation to your vertical). This is your starting position.
Pull the cables/weight down in front of your mid-chest line. Your arms should be slightly bent at the elbows. Bring the handle bars close enough to each other so that they are almost touching. After, return to the starting position and repeat again for desired number of repetitions.
Lower the weight in a controlled manner
Control the weight at all times by doing the exercise in a smooth and fluid motion
Don't hunch your back too much
Don't let the weight pull your arms up too much past your chest
Don't jerk the weight on the way down
SPECIAL NOTES & LEVEL of DIFFICULTY VARIATIONS
To increase the level of difficulty, either slow down the motion or increase the weight
This exercise is a very good exercise for the chest. If you are an absolute beginner this may not feel like the most comfortable exercise because of the bent-over position. Nevertheless, you shouldn't give up on it because it's a useful exercise for carving out your chest area.
The important thing to point out is that proper positioning and posture is key to executing the movement correctly. Thus, take your time with getting into position and adjusting your back so that it's not hunched over too much.
Once you do this exercise for a while it will seem less awkward and at some point you will get very comfortable with it.