Standing Machine Leg Curls are very similar to lying leg curls, just with a different machine.
Starting Position: Stand with one leg in front of the ankle rest. You should be leaning forward a little with you other leg planted on the ground.
Performing exercise: Slowly lift the weight with your heel as your legs curl in. Once your hamstrings are fully contracted, slowly lower the weight back to the starting position. Alternate this lift between legs.