Lower the bar down to the knees, as if you were doing a Romanian deadlift.
Explode into a vertical jump while holding the bar. Do not pull the bar. The arms stay straight.
Don't lower the bar too slowly. Just keep it under control. Be sure to finish the hip extension; make yourself "tall." Don't be surprised if you jump backward a bit when you get it right.
Ever had one of those days where you just couldn't get into the flow of your workout? Or worse yet, you don't even make it to the gym? It's happened to all of us before. The mind is willing, but the body just isn't ready (or vice versa).