Hold weight by your chest. Make sure shoulders don't collapse forward (you should feel your upper back working the whole time to help stabilize). Keeping weight in your heel, step up, making sure you do NOT push off foot that is on the ground. The goal is to use the single glute/hamstring of leg that is stepping up. Your body will want to lean forward, so focus on keeping chest upright to engage abs without knee going over toe or dropping inward.