Get on the dip apparatus and steady the weight plate between your legs. You can keep your arms locked out while you do this to make it easier for you to stay up.
Once you are ready, lower yourself down until your lower chest is in line with the handle bars. Then, raise yourself back up but do not lock out your arms at the top of the movement. Repeat this movement for the desired number of repetitions.
Perform this exercise in a smooth and fluid motion
Spread your arms and elbows a bit outward to target the chest more and not your triceps
Don't lock out your arms at the top
Don't dip/lower yourself too low as this may result in shoulder injury
SPECIAL NOTES & LEVEL of DIFFICULTY VARIATIONS
To increase the level of difficulty, slow down the movement or increase the weight.
This exercise is not for beginners. Even regular dips (without the weight) are not for beginners. Thus, this is an advanced exercise that does wonders for your chest.
To do this exercise, you will need a proper weight belt. Most well-equipped gyms will have one. If not, buy one because they are relatively inexpensive (if you buy nylon ones - the leather ones may be a bit pricy).
Doing dips will also strengthen your arms. Although the primary target group is your chest, your forearms, triceps and shoulders will get some exercise as well. It's important to note that if you keep your elbows tucked-in during this exercise, you will place more emphasis on your triceps. If you spread your elbows out you will be hitting your chest more (which is exactly what you want to do with this exercise).