This is a variation of the most popular abs exercise. The machine helps to work the abs in isolation.
Sit down on the machine. Grasp the handles.
Place your feet under the pads.
As you exhale, crunch your torso slowly.
Pause for 1-2 seconds at the top and, as you exhale, slowly return to the starting position.
Don't use heavy weight in this exercise. It can lead to injury easily.