This is a modified forward lunge that is done in an upright posture.
Start by standing with good posture and even light weights in each hand. Maintain the exercises through the exercise. Here are the 4 steps:
Take a step forward, then pause.
As you keep your back straight lower your body slowly and place your forward knee on the floor; pause.
Raise your body straight up; then pause again.
Bring yourself back to a standing position.
Then repeat this exercise for the other leg. Remember the pause between each step and keeping good posture.