The first step to this exercise is getting your initial bench setup in place.
To do this, you can either take a decline bench and elevate the bottom of the bench on top of a box or some other platform, or you can use a flat bench and elevate both ends.
However you choose to go about it, your basic goal is to get the bench parallel to the floor (a slight incline or decline is no big deal), and to have it high enough off the ground so that you can fully extend the dumbbells below you and perform the exercise safely.
Once your bench is setup, simply lay facing down with your chin pressing against the top of it. Hold onto a pair of dumbbells with your palms facing in, and then row them upward toward your midsection until you feel a strong contraction in your back muscles.
Lower the dumbbells back down until your arms are fully extended below you and repeat.
