The dumbell bench press is a compound exercise that primarily works the chest muscles, but also the shoulder and tricep muscles. It is a diverse exercise that can be performed to target working the upper, middle and lower portions of the chest muscles, when the exercise bench is set to an incline, flat, or decline position respectively.
Begin the exercise by grabbing two equally loaded dumbells and sit on the end of the exercise bench with the two dumbells resting on your upper thighs. Lie back on to the bench somewhat quickly, push up, and catch the dumbbells with your arms. While this does seem simple enough it does take some time to get used to it and proper form is essential for safety, especially when using heavier dumbells. Once you have the dumbells in hand with your arms in the extended position, proceed to press the dumbells upward until your arms are slightly bent at the elbows and lower them until the point that the hand bar of each dumbbell does not go lower than the chest. Here you can imagine that you are pressing a barbell that you could not lower below the chest as it would physically hit the chest. In the same way you would not want to lower dumbells below this point as you would be stretching the chest muscles more than is safe. Additionally, using lighter weight as you begin to perform the movement to get started as well as feeling how your body reacts during the movement will give you a feel for the optimum range of movement during the exercise. During the exercise, once you have reached the downward position, just press the dumbells upward to the point once again where elbows are slightly bent and repeat for the desired number of repetitions.
The great thing about performing dumbell bench presses is that there is no way one arm can cheat and press more than the other as with barbells (unless of course you are bouncing the dumbells off your chest which is not good or safe form). At the top of the movement, the dumbells should not touch or bounce off one another as this may reduce the exercise effectiveness or be dangerous, especially if using heavier weight. The dumbell bench press exercise like push ups is a great exercise for building and strengthening chest muscles.
Consult a physician before beginning a resistance training program to determine your health condition suitability to perform such exercises. Working with a physical trainer will reduce your chances of injury while performing this are any other prescribed exercise. Plan to always use extreme caution when performing this or any other exercise movement, especially if it is a movement you are not familiar with.