Place the necessary weight on your back like you're doing a squat. Then place one foot on the bench. Without the help from the foot on the ground, step up, pause for 1 second at the top of the exercise, then slowly drop back down to the ground. You want to resist on the way back down to the starting stance to get the benefits of both the concentric and eccentric phases of the lift. Also make sure to pause for 1-2 seconds at the top of the lift.